- NEW!
Answer to:
Beginer's question for and only for Mr Blaylock.
What is the binding energy er nucleon of 12/6C..Carbon 12.6 Since wecannotr use sub nor superscripts here?
For and only for Mr Blaylock:
92 MeV
(take the mass of the protons and neutrons, subtract the mass of the nucleus, divide by 12)
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Answer to:
At what speed is the kinetic energy of a particle equal to its rest energy?
It never is. Kinetic energy is (1/2) m v^2
so even at the speed of light, that's still only half the rest energy.
Answer to:
Let S3 be the six digit numbers whose one's digit equals the number of 3's appearing in the number. find the number of S(3) numbers
It doesn't seem worth making a special formula. Just look at each in turn:
Last digit = 0, 8*9*9*9*9*1 numbers.
Last digit = 1, first digit 3: 1*9*9*9*9*1
Last digit = 1, first digit not 3: 8*1*9*9*9*1 * 4
Last digit = 2, first digit 3: 1*1*9*9*9*1 * 4
Last digit = 2, first digit not 3: 8*1*1*9*9*1 * 6
Last digit = 3, first digit 3: 1*1*9*9*9*1 * 4
Last digit = 3, first digit...
Answer to:
When (ax^3-4x^2+5x-3) is divided by (x+2) and (x+1) the remainders are equal, find 'a'?? HOW THE HECK DO YOU DO THIS?
Synthetic division.
I know you stated the question wrong, but suppose I do it for the question you asked, and then you can do it the same way for the correct question.
ax^3 - 4x^2 + 5 x - 3 is a polynomial
It's a bit like a decimal number:
1248 is 1*10^3 + 2*10^2 + 4*10^1 + 8
If I divide it by 10 + 1, long hand:
1*10^3 + 2*10^2 + 4*10^1 + 8
1*10^3 + 1*10^2 (is 1*10^2...
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Answer to:
Solve: 27(1 1/9)
27(1 1/9)
is
27 times (1 1/9)
is
27 times (1 and a ninth)
is
(27 and a ninth of 27)
is
your turn.
Answer to:
In the compound interest formula
A=P((1+(R/N))^(NT))
what does N equal
what does R equal
what does T equal
A=P((1+(R/N))^(NT))
P is initial capital
A is accumulated capital
R is yearly rate
N is number of payments per year
T is term (number of years over which compounded)
Answer to:
Evaluate the definite integral:
(1)∫(9) [ (4x^2+3) / (√x) ] dx
(the integral is from 1 to 9)
I have been trying to do this problem for hours and I have had no success, please help! Explain any work if possible, thank you!
I would try u=sqrt(x)=x^0.5
du/dx = 0.5 x^-0.5
so 2du/dx is part of your question already.
You have [4x^2 + 3]/sqrt(x)
which is [4x^2 + 3] * 2 * du/dx
= [4 u^4 + 3 ] * 2 * du /dx
Using the chain rule this becomes:
= Integral u(0) to u(9) of [ 4 u^4 + 3 ] * 2 du
which is a simple one.
It's clear this is the way we were intended to do it because u(9) is a nice round number.
...
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Answer to:
A Norman window is in the form of a rectangle below a semicircle. If the outside perimeter of the window is 10 ft, find the dimensions of the rectangle (length and width) so that the area of just the rectangle is maximized.
perimeter of half a circle = half pi times diameter = half pi times width of rectangle.
Equation for perimeter =
(half pi + 1) * width of rectangle + 2 * height of rectangle = 10
Quantity to maximize: width * height.
Introduce two variables x = width*(half pi + 1)
y = height*2
Now x + y = 10
and the quantity to maximize is x y multiplied by a constant - same as maximizing x y
y =...
Answer to:
How do you find the integral of
3N^3((6N^4+5N+8)^7) without multiplying out the whole equation first?
You can't. If you imagine it written out, there will be large even powers which when integrated are going to make large odd denominators which won't cancel.
However, if it weren't for the '5N' it would be a simple substitution. So could the 5N part be wrong?
Answer to:
Given: F(x) = x2, find [F(x+h) - F(x)] / h
and simplify.
If F(x) = x^2
Then
F(2) = 2^2
F(3) = 3^2
F(banana) = banana^2
F(x+h) = (x+h)^2
F(x) = x^2
[F(x+h) - F(x)] / h = your turn
The remaining step is not calculus it's algebra.
You have to do some algebra before you attempt calculus. Are you in the right class?
Answer to:
Let
G(x)= (1∫ x) xt dt
(integral from 1 to x)
Find G' (x).
I'm extremely lost in my calculus class! Please explain any work if possible! Thank you :)
You have G(x) = integral of 1 to x of f(t) dt
where f(t) is some function of t.
You can integrate f(t) indefinitely to make F(t) + C all this means is to find some F(t) whose derivative F'(t) is f(t)
Then integral of 1 to x f(t) dt is then defined as F(x) - F(1)
If G(x) = F(x) - F(1)
then G'(x) = F'(x) because F(1) is constant.
And F'(x) is f(x) because that...
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Answer to:
Use the Second Fundamental Theorem of calculus combined with the Generalized Power Rule to evaluate the integral:
(integral from zero to pi/2) [(sin^2)3xcos3x(dx)]
I'm extremely lost in my calc class! Please help and show any work if possible!
I'm not sure what the "Second Fundamental Theorem of Calculus" is supposed to be.
But the integral you mentioned looks like
integral f(u) (du/dx) dx
where du/dx is cos 3x
In such a case, you can use the substitution rule, sometimes confusingly called the chain rule, which turns:
integral (between x1 and x2) of f(u) (du/dx) dx
into
integral (between u1 and...
Answer to:
Given: f(x) = x2 + 2x + 1, find f(x + h) and simplify. I have no clue how to do this. Please help me?
x^2 stands for x with a superscript 2
x^2 means x*x
2x means 2*x
* means 'multiplied by'
if
f(x) = x^2 + 2x + 1
then
f(1) = 1^2 + 2*1 + 1
f(2) = 2^2 + 2*2 + 1
f(3) = 3^2 + 2*3 + 1
f(banana) = banana^2 + 2 banana + 1
f(x+h) = (x+h)^2 + 2(x+h) + 1
You then use the distribution rules to simplify this:
a*(b+c) = a*b + a*c
and
(e+f)*g = e*g + f*g
Using the first...
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Answer to:
There two identical heavy springs, one foot each when un-stretched. When one spring is suspended from the ceiling it enlongates under its own weight to 2 feet. How long are two spings suspended from the ceiling in series?
Nice puzzle.
A single spring won't stretch evenly but more at the top which is carrying more weight than at the bottom.
Each small piece of spring of length dl at height L will stretch to (1+kL)dl for some k if the spring behaves linearly. This integrates to L + kL^2/2.
Over the whole length of the spring this sum comes to (1 + k/2) feet.
and we also know this sum is 2 feet, so k =...
Answer to:
What is the amount of matter ina given volume of space?
The density of a substance is defined as the amount of mater in a given volume of space.
Given the density of a substance, find amount of matter by multiplying by the volume.
Answer to:
How do we find the exact value of sec(-25rad/6)?
Usually, by
1) Write it in degrees instead of radians.
2) Use the periodic and symmetric nature of the trig functions to get the value in the range 0-90
3) Compare it to one of the standard triangles 30-60-90 which is half of an equilateral triangle of side 2, and 45-45-90 with the legs side 1
2pi rads in a circle
-25pi/6 divide by 2pi = -25/12 circles
= -25/12 * 360 degrees
= -25*30...
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Answer to:
X&y are #s such that pi/4 = tan-1(x)+tan-1(y). Give formula for pi/4 as sum of 2 series: one with x and the other with y. Explain why pi/4 can be better approximated, using fewer terms from the 2 series, if x&y are as small in magnitude as possible.
The series for tan^-1(z) contains increasingly large powers of z.
If z can be made small compared with 1, then the large powers will become insignificant.
(Example, if z=0.1 then z^5 = 0.00001)
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Answer to:
Suppose that X~binomial (3,p) where p is unknown. We observe X=2. Write down P(X=2) and what value of p maximises P(X=2). Please Help!
P(X=i) is nCi p^i q^(n-i)
You have to learn this of the binomial.
q=1-p
The maximum value for P(X==i) occurs when p = i/n
You can find that by differentiation:
P'(X=i) = nCi (i p^(i-1) q^(n-i) - (n-i) p^i q^(n-i-1))
Take out p^(i-1)q^(n-i-1) as a common factor:
P'(X=i) = nCi (i p^(i-1) q^(n-i-1))( i q - (n-i) p )
maximum when i (1-p) - (n-i) p = 0
i-ip-np+ip=0
...
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Answer to:
Find the number of 3 digits numbers whose digits add up to nine.
Ending in 9: none
Ending in 8: 108
7 - 117 207
6 - 126 216 306
5 - 135 225 315 405
4 - five numbers 144 to 504
3 - six numbers 153 to 603
2 - seven numbers 162 to 702
1 - eight numbers 171 to 801
0 - nine numbers 180 to 900
So 0+1+2+3+4+5+6+7+8+9 = 45 numbers in all.
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Answer to:
The minimum number of cards to be dealt from an arbitrarily shuffled deck of 52 cards to guarantee that 3 cards are from the same suit is
a)3
b)8
c)9
d)12
If I have a hand of cards where I have no more than 2 cards in each suit, the most cards I can have is 2 hearts + 2 diamonds + 2 spades + 2 clubs.
8 cards is the most I can have and not have 3 cards in a suit.
Therefore 9 cards guarantees 3 cards in at least one suit.
Answer to:
Is there a special term for a complex number in which the real part and the imaginary part are the same?
Zero.
The real part is always real.
The imaginary part is always pure imaginary except at zero.
They can only be equal if the complex number is zero.
Answer to:
Evaluate the integral by interpreting it in terms of areas.
(-5)∫(5) [√(25-x^2)] dx
Im so confused in my calc class! Please explain any work that you can! Thank you!
The square root part is part of the equation of a circle.
If you have a circle of radius 5, then
x^2 + y^2 = 5^2
y^2 = 25-x^2
y = sqrt(25-x^2) is the upper half of the circle.
Integrating this wrt x gives the area of the upper half of that circle. Now all you have to do is multiply the area of half of this circle by the constants in the integral.
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Answer to:
How many solutions does the equation sin(sin(sin(sin(sin(x)))))=(x/3) have?
Three.
-1.856, 0, 1.856
approximately.
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Answer to:
Can anyone give the correct answer with a reason to it? 2,3,6,__,28.Thank you.
2, 3, 6, _, 28
It's 13.5 but I'm struggling to come up with an easy explanation.
The best I have is if you take third differences of the cubes you get a constant:
1, 8, 27, 64, 125
Take the differences:
7, 19, 37, 61
second differences:
12, 18, 24
third differences:
6, 6, ...
If your formula is made of squares and cubes it must do the same thing. The third difference...
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Answer to:
Hey everyone! im working on a math project for school and i was wondering who could help. Q 1: what do positive and negative slopes look like? Q 2: what does the slope of 1 look like and what is it? thanks so much for all your help! thankyou thankyou! :)
Positive slopes slope up.
Negative slopes slope down.
a slope of 1 goes up as much as it goes along.
and for extra:
a slope of 2 goes up twice as much as it goes along.
Does this help?
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Answer to:
If $60 is estimated to be the average fuel cost (f)
and the monthly hanger rental is $3,000- what would be the equation for the profit, P, in terms of x?
You haven't said what x stands for.
To find profit, find turnover (money coming in) and subtract outgoings/costs.
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Answer to:
How do you prove Pythagoras' Theory of a^2+b^2=c^2?
There are more than 400 proofs. The one that I found easiest to understand was: Draw a square of side a+b units.
Going clockwise mark a units along each side. Join these four points to make a tilted square and four triangles.
Each of the triangles has sides a,b,c and an area of half ab.
All four triangles sum to 2 ab
The large square has an area of (a+b)(a+b) = a^2 + 2ab + b^2
So the...
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Answer to:
Need a little help with some simple things:
If 100% are divided into parts of 1:2:3:4 . How do I calculate how much "%" each of them has? To clearify this case, the "1" has the highest per cent attribute, 4 the lowest.
Thanks!
If 100% is divided into ten parts (count 1+2+3+4) then
each part must be 10%
and the four slices are 10% 20% 30% and 40%
Unfortuantely your "clearification" has it the other way, so I'm not sure what you mean.
Answer to:
To add numbers with different denominators, a student is consistently using the product of the denominators as a common denominator. Is this correct? Why or why not?
The worst that can happen is that the resulting numerator and denominator have common factors so that the resulting fraction is not in its lowest terms.
For some applications, this doesn't matter.
If the student "cancels" factors from the numerator and denominator after the addition to bring the fraction to its lowest terms then his method will probably be quicker if there...
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Answer to:
ABCD is a rectangle with a point P on its interior. The distance from P to the vertices are x,y,z and w. Prove that x^2+z^2=y^2+w^2
Each of the values x^2,y^2,w^2,z^2 can be written as the sum of two squares. For instance, if x is the distance of P from A, then x^2 is the sum of X1^2 + Y1^2 where X1 is the difference in x coordinate from P to A and Y1 is the difference in Y coordinate from P to A.
Take two opposite corners and you get the sum:
X1^2 + X2^2 + Y1^2 + Y2^2 whichever pair of corners you take.
Answer to:
What does it take to prove that all circles are similar, that is similar in strict geometric sense? 'Cause if not all circles are similar, then how can we use the same constant π=22/7 for a ratio of circumference to diameter of all circles?
Such a proof depends on your definition of how you measure the length of the circumference.
One way is to find a series of polygons whose vertices lie on the circle, find the perimeter of the polygons and find the limit that the perimeter approaches.
Suppose you have two circles, one diameter 1, one diameter 2.
You can repeat the polygon process with both circles. At each stage, the...
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Answer to:
I am greater than four tens & less than five tens, I have nine ones, what am I?
You are 49.
4 tens and 9 ones.
(Used to be 4 tens and 9 UNITS when I learned it)
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Answer to:
What is the most weird way to measure the number π?
Add up the series:
1 + 1/4 + 1/9 + 1/16 + 1/25 + ...
Multiply by six.
Take the square root.
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Answer to:
How do you factor 3x + 3?
You know the answer, but how to get it?
You're looking for two expressions A and B, neither of which are 1, which multiply to make 3x + 3
Here are some ideas::
1) If the expression is a sum of terms, all of which have a common factor, then you can use that as A.
Example in 33 = 30 + 3, 30 and 3 have a common factor of 3, so 3 is a factor of 33.
2) Maybe you can rearrange and...
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Answer to:
Let's say I'm playing a game where for each bet I have a 49% chance of winning but I am only paid 1:1 if I win. If my betting size is constant, what is the likelihood that I have a net win after 10 trials? After 100? Aside from the answer, how do I go abo
If I understand you correctly, the only way you are winning after ten trials, is by winning every one.
In any case, the formula you need is the binomial distribution.
Put p = 0.47
q is always 1-p
Probability of i events out of n occurring is nCi p^i q^(n-i)
nCi is the binomial coefficient and is calculated like this:
7C3 = (7*5*4)/(3*2*1)
Same number of factors on the top as on...
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Answer to:
What is the Russlle paradox?
Russel's paradox defines a set which contains all and only those sets which do not contain themselves.
Does it contain itself?
If it does, then it doesn't match its own definition, because it should only contain sets that don't contain themselves.
If it does not contain itself, then why doesn't it, because it's supposed to contain sets that do not contain...
Answer to:
At what point is the Mandelbrot set considered the Julia set?
Both Mandelbrot and Julia sets are created by iterating the action:
x -> x^2 + c
But while the Mandelbrot starts at zero and varies c, a Julia set keeps c constant and varies the starting value of x.
Each point of the Mandelbrot set corresponds to a Julia set.
The Mandelbrot set cannot be considered to be a Julia set.
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Answer to:
Does anyone know Times table tricks?
The three times table is easier to remember if you write it in a 3x3 grid like this:
03 06 09
12 15 18
21 24 27
Notice how the units count up the columns and the tens increase with each row.
There are also nice patterns with the seven times table:
07 14 21
28 35 42
49 56 63
Look how the tens increase by 2 in each column, and by one in each row. The units are the other way...
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Answer to:
How do I make t the subject? x^2 = (t - 3) / (2t + 1)?
Need to get t on its own.
First multiply by (2t+1) to get rid of fractions:
x^2(2t+1) = (t-3)
multiply out:
2 x^2 t + x^2 = t - 3
Put the t terms on one side:
2 x^2 t - t = - 3 - x^2
factorize the left hand side:
(2 x^2 - 1) t = -3 - x^2
divide
t = (-3 - x^2) / (2 x^2 - 1)
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Answer to:
Could anyone please tell me, if 25 increased by 25% over 3 years, how much would it be? I suck at maths
There are four different answers to this question:
A:
If something is increased by 25% it doesn't matter how long it takes, an increase of a quarter is an increase of 6.25 which takes it to 31.25
B:
But perhaps the question means, if it increases by 25% over 3 years, how much does it increse in one year.
25% of 25 is 25/100 of 25 = 625/100 = 6.25
If that's three years...
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Answer to:
Maths. trying to find mass of a shape that's bound by a curve and lines. lies on the xy plane. density is given by a particular function. Think I need to find the area integral of a function bound by these graphs, but what function?
All you need is the area of the shape multiplied by the density.
If you trace the boundary on graph paper with a pencil, your pencil may increase or decrease in x.
Mark each of the points where the boundary of the shape changes from increasing in x to decreasing in x.
And also when it changes from decreasing in x to increasing in x.
For each segment of boundary you now have you can get the...
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Answer to:
How close to 2 do we have to take x so that 5x+3 is within a distance of 0.075 from 13.
I am confuse on how to evaluate this problem.
Let the "closeness" to 2 be represented by c. c can be positive or negative.
Then x = 2+c
substitute in:
5(2+c)+3 within a distance of 0.075 of 13
13 + 5c within a distance of 0.075 of 13
0 + 5c within a distance of 0.075 of 0
5c within a distance of 0.075 of 0
c within a distance of 0.015 of 0
closeness to two = within 0.015
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Answer to:
F(x) =x^2 |x^2-1| < 1/2 whenever |x-1| <delta correct to four decimals round down if necessary
F(x) =x^2 |x^2-1| < 1/2
if x is zero or 1, then F(x) = 0, which is less than a half, so x near zero or one fits, I assume the 'whenever |x-1| <delta' means find the answer for when x is near 1.
The region near x=1 where F(x) is less than a half is bounded by the points at which F(x) = 1/2
So x^2 |x^2-1| = 1/2
if x>1 then
x^4 - x^2 - 1/2 = 0
Which is a qudratic...
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Answer to:
If f(x)=x-3 and g(x)2x-4, find (f+g)(x)
If f(x)=x-3 and g(x)2x-4, find (f+g)(x)
(f+g)(x) = f(x)+g(x)
= 3x-7
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Answer to:
If f(x) = x^2 +1 and g(x) =2x, find (f of g)(x)
(f of g)(x) = f(g(x))
f(anything) = anything^2 + 1
f(g(x)) = (g(x))^2 + 1
but g(x) = 2x
f(g(x)) = (2x)^2 + 1
= 4x^2 + 1
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Answer to:
There's a high amount of nitrogen in the atmosphere, so why aren't we breathing excess amounts of nitrogen dioxide daily?
It takes energy to form nitrogen dioxide from nitrogen and oxygen so the nitrogen and oxygen in the atmosphere stay as separate gases, and there are only tiny amounts of nitrogen dioxide in the air
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Answer to:
Integrate S[t^(9)e^(1+t^(5))] dt using integration by parts if possible. Thanks!
To integrate by parts:
If A' denotes the derivative of A wrt x then
(u v)' = u v' + u' v
Integrating both sides:
[u v] = Integrate (u v')dx + Integrate(u' v)dx
Rearrange:
Integrate(u v')dx = [u v] - Integrate(u' v)dx
When you use integration by parts, one factor needs to be integrated (v' on the left becomes v on the right) and...
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Answer to:
If the end piont is (-8, -1) and the midpoint is (0, 3) the what is the other end point? same question with these other coordinates; endpoint(-5, 9) and midpoint(-8, -2) and coordinate; endpoint (-3.5, -6) and midpoint (1.5, 4.5)
Start point (-8, -1)
mid point is (0, 3)
You moved +8 units in x and +4 in y to get to the mid point.
You'll have to move the same distance again to get to the end point.
Same method with the others.
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Answer to:
Sketch six points U,V,W,X,Y and Z on four lines such that each line contains three points?
Draw a four sided shape with no parallel sides.
Label the corners U,V,W,X
Extend opposite pairs of sides until they cross. The two crossing points are Y and Z.
There are four sides = four lines.
Each side has two corners, plus one crossing point = three points per line.
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Answer to:
X^2=x^3, give two possible values for x. Please show how to work out problem.
If x^3 = x^2
Then x^3 - x^2 = 0
factorize:
x^2 (x - 1) = 0
Any of the three factors, x, x, and (x-1) could be zero.
x could be zero, giving x=0
x could be zero, giving another x=0 (a double root)
(x-1) could be zero, giving x=1
Answer to:
Can u tell me if this is right?1. (3+5)(2x^2 - 7x + 4) answer (3x +5)(2x^2 -7x +4)=(3x)(2x^2 -7x +4 ) +(5)(2x^2 -7x + 4 ) =(3x)(2x^2) -(3x)(7x)+(3x)(4)+(5)(2x^2)-(5)(7x)+(5)(… -21x^2 +12x +10^2 -35x +20 =6x^3-11x^2 -23x +20
Yes the answer is right, I didn't check your working. (3+5) should be (3x+5) of course.
Answer to:
I know there are theories on constant expansion into an infinite space etc. but where/when did it all start. How did the first hydrogen atom come to be in an infinite amount of space. I cant comprehend infinite time. any theories on it?
I think you have misunderstood the expansion of the universe.
It doesn't expand *into* space. There isn't this bit of universe which is expanding and then void outside. The whole thing expands.
The classic analogy is flat beings living on the surface of an expanding baloon. All the surface of the baloon expands.
However, this can confuse: in 3D we see the baloon expand...
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Answer to:
If you have 25% dextrose solution and 10% dextrose solution, how many ml of each do you need to make 1000 ml of 20% dextrose solution?
Take A ml of 25% and B ml of 10%.
A + B = C = 1000ml
Amount of dextrose: 25% A + 10% B = 20% C
Solve for A and B.
Multiply second equation by 10:
250% A + 100% B = 200% C
subtract first equation:
150% A = 100% C
A = 2/3 C = 667ml
B = C-A = 333ml
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Answer to:
Which months have 5 weeks
None of them have a whole five weeks. All of them use at least part of five weeks, with the occasional exception of February.
Answer to:
If the fundamental frequency of a guitar string is 220 Hz, what is the frequency of the second harmonic? Of the third harmonic?
It's not rocket science:
The root note is the 1st harmonic, the fundamental.
If the 1st harmonic is 220 Hz
the 2nd harmonic is 440 Hz
the 3rd harmonic is 660 Hz
The nth harmonic is 220 times n Hz
Incidentally, 440Hz is concert 'A' above middle C.
220Hz is an octave lower.
660Hz is E, an octave and a third above middle C.
Answer to:
What is the semi vertical angle of a cone?
The angle between the axis and a line in the surface which passes through the apex.
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Answer to:
Since 2001 and 2009 how many leap years have we had?
How can you not know that?
2004 and 2008
That's two.
Answer to:
5. The bus from Osaka to Tokyo will take 2 hours and 35 minutes the if the bus will leave 35 min past 8 in the morning what time will you arrived
in Tokyo?
a. 10:55 b.11:10 c.11:35 d.12:22 e.12:45
8:35 + 2h35 = 10:70
but 70 minutes is another hour plus 10 mins
10:70 = 11:10
Answer to:
How can I turn a liquid into a gaseous form without using heat energy? Please be quick!
Reduce the pressure until it boils.
Answer to:
What are the units on centimeters cubed divided by centimeters? Is it still cm^3 or is it now cm^2?
If you divide a volume (cm^3) by a height (cm) you get the average cross-sectional area (cm^2)
Answer to:
Answer this inequality:
3x > 2x +12 ????
any answers?
Subtract 2x from both sides of the inequality. The idea is to get x by itself on one side.
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Answer to:
What is the most dangerous scientific research, to humanity, being conducted at present? (And these are just the ones of which we are aware!).
I think biological disease research is the most dangerous.
A single nasty organism could wipe out the human race.
No other field can do that much damage. A nuclear explosion is only so big.
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Answer to:
Is science failing to communicate and, if so, why?
Yes I think it is failing to communicate with the masses, and I think it's because the people who have the brains to do and understand science don't go into media studies. Which leaves us with clueless journalists who can't speak coherently on the subject.
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Answer to:
What is the balanced symbol equation for the 'metal + acid' reaction of aluminium + nitric acid?
Nitric acid makes nitrates.
put Aluminium Nitrate into the wikipedia search box.
Look at molecular formula on the right.
Result: Al (NO3)3
So try Al + H NO3 = Al (N03)3 + H2
nope, three NO3s on the right. Try three NO3s on the left:
Al + 3 H NO3 = Al (NO3)3 + H2
All balances except the H. Need a multiple of both 2 and 3 H on each side. Multiply H2 by 3 and 3HNO3 by 2:
Al + 6 H NO3 =...
Answer to:
The Vector C is Perpendicular to vectors A & B, and the Angle between A & B is 30º
if the modules are:
|A| = 6
|B| = 3
|C| = 3
calculate the Scalar triple product
Triple product is (A cross B) dot C
V = A cross B is |A||B| sin 30 in the direction at right angles to A and B which happens to be C.
|V| = 9
V dot C = |V||C| cos angle
and since V is in the direction of C this is
|9||3| cos 0
Answer to:
Give one example of a motion where an object does not change its speed but its direction of motion changes continuously?
The motion of Venus about the Sun.
More or less.
Answer to:
A body starting from rest travels with uniform acceleration.If it travels 100m in 5s,what is the value of the acceleration?
This is the formula I was taught which does this for you:
s = u t + (1/2) a t^2
u is initial speed (0m/s)
s is distance (100m)
t is time (5s)
Plug in the numbers, solve for a (acceleration)
Answer to:
What is the value of cos15 and sin15?
cos 30 = sqrt(3)/2
cos 2x = 2 cos^2 x - 1
2 cos^2 15 - 1 = sqrt(3)/2
cos^2 15 = (2+sqrt(3))/4
cos 15 = sqrt(2+sqrt(3))/2
cos^2 x + sin^2 x = 1
sin^2 15 = (2-sqrt(3))/4
sin 15 = sqrt(2-sqrt(3))/2
Answer to:
Who do you think is the greatest physicist of all time?
Galileo. Science didn't really exist before him. He discovered a LOT. We think of Newton having discovered gravity, but Galileo knew all there was to Earthly gravity long before Newton.
He discovered the moons of Jupiter.
He described exactly how pendulums work.
He measured and explained the behaviour of bodies in motion.
He reasoned about terminal velocity.
He invented material...
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Answer to:
The force of gravity on Planet A is greater than the force of gravity on Planet B. On which planet will it be easier to push identical cars along a level surface? A. Planet A B. Planet B C. It will be the same on both planets. D. It depends on the weight
If the forces are only mildly different, then it will be easier to push the car where the gravity is stronger on planet A. Your increased weight will give you more traction on the surface as you push. The inertia of the car is the same on both planets.
If the gravity varies a lot, it might be different. If planet A has very strong gravity, you might have difficulty even moving yourself, let...
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Answer to:
How can galaxies recede faster than the speed of light?
Relativity doesn't mean you can't have speeds that are faster than light.
For example, imagine a lighthouse with a laser sweeping round once a second. One mile from the light house the light beam appears to move round at six miles a second.
200,000 miles out and the beam appears to move round faster than light.
If you see in the distance two spaceships that start together and...
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Answer to:
Find the value of sin^-1{ sin 5pi/6 }
sin(5pi/6) = sin(pi/6)
To better see this, if your angle starts on the x-axis and goes counterclockwise and the length of the arms is one, then sin gives you the height above the x-axis. pi radians is 180 degrees.
sin(pi/6) is the same height as sin(pi - (pi/6))
sin^-1 of that gives you all the angles that have that height: pi/6, 5pi/6 and any multiple of 2pi added to those.
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Answer to:
I have 6 random numbers between 1 and 49 which add up to 156, how do I work out how many other combinations of 6 numbers there are that add up to 156 by only using the numbers between 1 and 49?
I first read your question thinking you meant that numbers could be used more than once and that the order mattered and I worked out the answer would be 153287120.
But now I'm thinking you mean "lotto" numbers - you can't pick the same number twice, and if you pick 4 and 5, it doesn't matter which order you pick them in.
I got 163273 that way.
I cheated. I wrote...
Answer to:
The TV tube manufacturer has observed that on an average out of every 10000 tubes produced,5 are found to be defective.If a sample of 20 bulbs is selected,wat is the probabilty that no are defective.Wat is the probability that atleast two are defective?
Use the binomial distribution.
p = (5/10000)
q = 1-p
n=10000
Probability of i defective = nCi p^i q^(n-i)
nCi is the binomial coeffecient.
20C0 is 1
20C1 is 20
Use the formula to work out the probability that 0 area defective.
Use the formula to work out the probability that exactly 1 is defective.
Add those together to get the probability that at less than two are defective....
Answer to:
Find equations of the tangent lines to x^2+16y^2=52 that are parallel to the line 9x-8y=1
To solve this:
differentiate both equations wrt x.
Write m for the differentiation of y wrt x.
Solve for m, this is the slope of the lines.
Solve for pairs of (X,Y)
These are the points on the equation where the slope is right.
The equations of the tangent lines are:
(y-Y) = m (x-X)
where you substitute your found values for X,Y and m
Answer to:
The expressions 8g+4g and 12g are what because they donate the same number
They are "equal" and they are also "equivalent".
Answer to:
How do you write a function rule for a graph
Perhaps you are looking for a rule like this:
f(x) = x^2
Answer to:
What is a geometrical way to calculate the sum of all natural numbers from 1 to any given number?
The area under a staircase.
Each step is one unit high and one wide. The last step is n units high.
If you make two of these and turn one upside down and put it on top of the first you get a rectangle of size n by n+1
The sum you want is half that rectangle.
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Answer to:
In the equation -8 times -c, how do i explain that -c is equal to -1c?
-c is equal to -1
Perhaps you are trying to write:
(-8)(-c)
Not sure what you mean: -8 times -c isn't an equation, having no '=' in it.
Answer to:
When you look in the bathroom mirror then step back do you see more of yourself less or the same. Just answer dont go look.
Too late. As soon as they mentioned it on 'Bang goes the theory' I had to try it.
I still don't quite understand it.
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Answer to:
Where is River Tam?
Hi Hungry Guy.
Do you mean an actual river? (or the sci-fi character?!)
There is a river "Tam" or "Tan" in Guangdong, China.
I thought the river Tam ran under the highest bridge in the world, but apparently, that's the Tarn!
There's also the river Tame, which is a few miles from me, and is sometimes called the Tam - for instance in the name of the town...
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Answer to:
If the Canadian dollar is worth 22% less than the U.S. dollar, then the US dollar is worth what percent more than the Canadian dollar?
If the Canadian dollar is worth 22% less than the US dollar, it's only worth 78 cents. (100 cents - 22% of 100 cents)
The US dollar is worth 22 cents more than that.
So the question asks what percentage is 22 US cents of the Canadian dollar.
What percentage is 22 US cents of 78 US cents?
22/78 * 100 = 28.205%
The US dollar is 28.205% more than the Canadian.
In other words...
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Answer to:
A box contains 10 green, 2 red, 7 yellow, and 6 blue marbles. Four marbles are drawn from the box without replacement. a) What is the probability that all four marbles are the same color? b) What is the probability that n
For (a) it is easier to calculate "what is the probability I will get four green marbles" then repeat the math for each color and add them up (you can add them because the events are mutually exclusive)
To calculate the probability of four green, well its the probability of the first one of the 25 marbles being green, multiplied by the probability that the second marble of the...
Answer to:
Find the euation of the tangent line to the curve: y=6x^(2/3) -3/x
It could be done with limits.
if (x1,y1) and (x2,y2) are points on the curve, then the line through these points is
y = ((y2-y1)/(x2-x1))(x-x1) + y1
The slope is (y2-y1)/(x2-x1) and is the only bit which uses y2 and x2.
Let x2=x1+delta : make the second point very close to the first and see what the line becomes.
x2-x1 = delta
what is y2-y1?
y2-y1 = 6(x1+delta)^(2/3) -...
Answer to:
If there are two series say a=6+11+16+.................. and b=12+21+30+39+48+57+.................... How we can find the number of common terms between the two series and the common terms itself. Kindly explain with steps.
It helps if you can find a formula for both series.
a[i] = 6 + (i-1) * 5
fits the first series.
b[j] = 12 + (j-1) * 9
fits the second series. Now we need to find numbers which fit both series.
6 + (i-1)* 5 = 12 + (j-1)* 9 for some i and j
subtract six:
(i-1) * 5 = 6 + (j-1)* 9
The left side is divisible by five. The right side needs to be divisible by five too.
Let j = 5k+r where...
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Answer to:
The average age of 8 men is increased by 2 years. When two of them whose ages are 20 and 24 years, are replaced by two new men. The average age of two new men is?
The easy way to do it is to assume that the other six men have only just been born and are age 0, and the replacement men have the same age as each other. It could happen!
So before, the ages are 0,0,0,0,0,0,20,24 and the average is 44/8 = 5.5 years
Afterwards the ages are 0,0,0,0,0,0,X,X, the new average is 2X/8 = X/4 and this must be 7.5 years
X = 30
If the two new men are both 30,...
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Answer to:
Large Hadron Collider. Support or Oppose? (no fighting plz)
Of course support.
The LHC is one of the most dramatic experiments mankind has ever done.
Those who oppose do so based on two counts:
1) superstition. They say the LHC will destroy the Earth.
But the truth is that if you looked at all the things mankind does, the LHC wouldn't be near the top of the danger list, but near the bottom. I doubt any experiment in history has ever had...
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Answer to:
What concert hall is famous for its acoustics?
The Albert Hall in London, UK
Symphony Hall in Birmingham, UK
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Answer to:
I think analysis is way more interesting than algebra. Do you agree?
I agree - I found analysis more interesting than algebra, but that's cause I was better at it. Algebra had stuff I never understood properly like Wedge products of vector spaces and Sylow group theory.
I think a lot of people have trouble with limits, and never get the epsilon/delta idea, so to those who get limits analysis seems easier than algebra.
Answer to:
An enclosed transformer has four wire leads coming from it. How could you determine the ratio of turns on the two coils without taking the transformer apart? How would you know which wires paired with which?
Pick any two wires and measure the DC resistance between them.
The two coils are electrically isolated, so if there is high resistance, you've picked wires on the different coils.
Try again until you get a low DC resistance. Those wires (A and B) are connected to the same coil. The other two wires (C and D) are connected to the other coil.
Put an AC signal across A and B. The ratio...
Answer to:
Numbers less than 500 that if you exchange the ones and hundreds place the new number is 396 more than the original number and if you exchange the ones and tents place the new number is 27 more
396 is 400-4
so exchanging hundreds and tens increased the hundreds place by 4 and decreased the units place by four.
Possibilities are 1x5, 2x6, 3x7, 4x8 and 5x9,
27 is 30-3
exchanging tens and units increased the tens by three and decreased the units by three.
Possibilities are x03, x14, x25, x36, x47, x58, x69
Put those together and the possibilities are:
125, 236, 347, 458 and 569
Answer to:
What is the correct name for this symbol (see answer) when it is used in a line graph to show that you have gone farther than what would have been allowed by your scheme, ie 0, 5, 10, 15, 20, 25, 30, 125.
It can be called a "scale break" symbol or a "broken axis" symbol
Answer to:
If 300 people buy a lottery ticket once a week, choosing 4 numbers from 1-24, how long could it run before someone wins?
Supposing the people pick their numbers at random then the chance that any particular person wins in any particular week is (1*2*3*4)/(24*23*22*21) = 1/10626
(it's totally untrue that people pick their numbers perfectly randomly but I'll have to go with that cause I don't know how unrandom people's choices are),
The chance of nobody winning in a particular week is...
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Answer to:
With my TI voyage 200, the derivative for sin(x)^2 is returned as 2sin(x)cos(x) in radian mode but Pi*sin(x)cos(x)/90 in degree mode for the angle. Is this a bug in the cas? How can the derivative depend be differ
That's interesting.
You calculator sees the sin and cos functions as different depending on the mode.
Let sin(x) be the "real" standard trigonometrical function acting on radians.
In radian mode your calculator's SIN(x) = sin(x)
In degree mode the calculator's SIN(x) = sin(pi x/180)
and COS(x) = cos(pi x/180)
So when you ask for the derivative of...
Answer to:
Why is photosynthesis essential for the survival of man?
What your teacher is thinking is that without photosynthesis, there are no plants, and since every animal eats plants or animals that eat plants, they would all die out leaving nothing for man to eat.
But teacher has failed to take into account that man can manufacture the essential ingredients of our food. It wouldn't be pretty and most of the human race would die out, but perhaps...
Answer to:
Simplify –j + 5(k + j). Justify each step.
if j is apple and k is orange.
subtract one apple from five lots of (apple + orange)
That's four apples and five oranges = 4j+5k
Justify each step! Why?!
Here's the long version:
-j + 5(k+j)
5(k+j) + (-j) [addition commutes]
(5k+5j) + (-j) [multiplication distributes over addition]
(5k+(4+1)j) + (-j) [definition of the number five]
(5k + (4j + 1j)) + (-j) [multiplication...
Answer to:
How many numbers from 1 to 200 have an expanded form that is identical to the standard form? what are they?
expanded form:
1 x 100 + 2 x 10 + 3
standard form:
123
The only time those two forms are going to be the same is if there aren't any 'x10' or 'x100'. The largest number for which this is true is 9.
Answer to:
Can someone explain to me what first order and second order logic are ? and how they're different?
There is a hierarchy of systems of logic which become progressively more powerful, and able to prove more statements.
You start with propositional calculus, also known as sentential logic. This can make statements like
If "It is raining" and "it is snowing" then "it is raining".
The quoted phrases are replaced with letters, and the logic treats them as...
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Answer to:
According to set theory is Φ = {Φ}
The set on the left is the empty set. It has no items in it.
It can also be written {}
The set on the right is not empty. It has exactly one item in it.
That item is an empty set.
The set containing an empty set as an item could also be written {{}}
Since the sets on each side of the equals have different numbers of items, zero on the left, one on the right, the sets are not equal.
Answer to:
Find the arc length of y = x^4 from the origin to (1, 1). Answer in length units, correct to two decimal places, please. a. 1.44 b. 1.48 c. 1.52 d. 1.55 e. 1.60 f. none of these
Suppose I approximate the curve with two straight lines.
One straight line from
(0,0) to (1/2,1/16)
and the other from
(1/2,1/16) to (1,1)
The length of the first line is sqrt(65)/16 = 0.5039
The length of the second line is 17/16 = 1.0625
Total length of lines = 1.5664
This is an underestimate, as the straight lines take a short cut.
This rules out answers a,b,c and d, without you...
Answer to:
I baked 27 cupcakes. One of them contains my wedding ring. I have a scale of justice and can use it 3 times. How do I determine which cupcake contains the ring?
Eat the cupcakes until you find the ring.
OR
Weigh nine cupcakes against nine.
The heavy side is the side with the ring.
If they balance, the ring is in the remaining nine that you didn't balance.
Now you have it down to one of nine.
Weigh three against three.
Same idea.
Now you have narrowed it down to one of three cupcakes.
Weigh one aginst one.
Same idea.
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Answer to:
What are some current AND valid scientific explanations for solar system anomolies like the perturbations in the orbits of Neptune and Uranus as well as their irregular axis tilts and reasons for the existence of the asteroid belt?
What perturbations of Neptune and Uranus?
Axis tilt: Planets are formed when protoplanets collide. If rotating protoplanets hit a glancing blow, the resulting body can have an axial tilt.
When one planet forms, it disrupts the formation of planets in nearby orbits. The asteroid belt never forms a planet because Jupiter and Mars perturb the orbits of the asteroids so they do not share the...
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Answer to:
My grandfather clock worked for years, now stops. With the pendulum off, I move minute hand clock will go for a couple minutes. Do you have any ideas?
Needs cleaning and lubrication?
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Answer to:
How does cyanide tastes?
It tastes of almon...arrgh...donk.
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Answer to:
Eventually the poles are going to switch, as they have done many times in Earths existence. North will become South and vice versa. What will happen to any flying planes when this occurs?
Based on every single switch in the past, it takes thousands of years to do a complete flip.
Long before this happens, the Earth will be hit by a major Solar flare from the Sun, this will knock out a lot of our communications, and it is likely that we will have to fix that problem good, before we have to worry about lack of a magnetic field.
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Answer to:
What exactly is a function? (In lamen's terms). When dealing with Limits of Calculus, what does it mean to have a "hole" in the graph?
A function has an input set and an output set.
The input and output set might be the "set of real numbers"
A function maps some elements in the input set, to elements in the output set.
For each element of the input set that the function can handle, it produces a single element from the output set.
If the function is complete it maps all elements in the input set.
If the...
Answer to:
What is the domain and range of the function f(x)= √(16-x^2)
The domain is the allowed values for x.
From the question we could guess that x must be a real number between -4 and 4 inclusive, because a square root of a negative number would be imaginary, and if x is outside that range, that is what would happen.
A function is a kind of map from one set to another.
The definition of a function is not complete without specifying the sets in question,...
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Answer to:
Creationist Mathematics question: If light was slowing down exponentially and now it travels at 186,000mps and it started coming toward us 6000 years ago from the farthest star, and the farthest star is 7.6X 10^19 miles away, how fast was light going
A light year is about 5.9x10^12 miles, so the star you gave is 1.3x10^7 light years away.
"slowing down exponentially" would mean that
speed_of_light_at_time_t_years_ago = c e^(k times t_years_ago)
Distance travelled by light in time t = integrate speed with respect to time.
Distance travelled by light in last 6000 years
[(c/k) (e^(6000 k) - 1)] = 1.3x10^7
(c is exactly...
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Answer to:
Q=B√(A^2D^2/A^2+D^2) how do i make D the subject?
square both sides
multiply both sides by A^2 + D^2
you get:
Q^2(A^2 + D^2) = B^2 A^2 D^2
Subtract Q^2 D^2 from both sides:
Q^2 A^2 = D^2 (B^2 A^2 - Q^2)
Divide both sides by (B^2 A^2 - Q^2)
(Q^2 A^2)/(B^2 A^2 - Q^2) = D^2
Square root both sides:
+/-sqrt((Q^2 A^2)/(B^2 A^2 - Q^2)) = D
Answer to:
If an object slows down from 5m.s-1 to 3m.s-1 in one second, it undergoes a negative acceleration of 2m.s-2 – True?
On average yes, but the acceleration can go above or below that figure during that second.
Answer to:
Other than the famous "Wow!" signal, have there been any other possible signals picked up by SETI?
There are lots of Wow-like signals recorded over the years, as the SETI telescope continuously scans the sky, so telescopes are trained on where the interesting signals came from to look for the signal again and it is not there.
Without being able to find the signal again, it is not possible to prove that it was not a communications satellite that just happened to go overhead or some other...
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Answer to:
Why do you suppose that pitchman John Cameron Swayze NEVER slid his tongue over a TIMEX® watch during one of the those TV commericials in the 50s & 60s & 70s, before proclaiming, "It takes a LICKING & keeps on ticking!"?
The point is that the watch is tough, not that it is resistant to human tongues!
LICKING as in beating.
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Answer to:
A tree has 3 vertices of degree 2, 2 vertices of degree 3 and 1 vertex of degree 4. If the remaining vertices have degree 1, how many vertices in the tree?
I would solve this by drawing it.
But failing that:
Take the vertex of degree 4,
four loose edges attached.
pick an edge and attach a vertex of degree 3
now you have five loose edges (one went in, two out).
pick an edge and attach another vertex of degree 3
now you have six loose edges.
The edges of degree 2 make no difference to the loose edges.
All six loose edges must have a...
Answer to:
When a crystal of copper sulphate is placed at thye bottom of a beaker containing water,the water slowly turns blue why?
I answered this once but AB seems to have lost the answer.
When copper sulphate, which is blue, is added to water, it dissolves, which turns the water into copper sulphate solution, which is blue.
Copper sulphate is blue because it actually has water within it. It's full name is copper sulphate pentahydrate : there are five molecules of water bound into the copper sulphate crystal...
Answer to:
Who has the lowest score on answerbag. Are there any people with minus figures out there?
The lowest score on AB dates from before the point system.
Before the point system you got a percentage and a score like A+ or F-.
The bottom of the ranking was someone who had the lowest possible score of 0% F-- and was at the bottom of the board.
I think he rapidly got to bottom place because his answers were advertising spam, and there were several of them.
He was last seen Aug 25,...
Answer to:
When I was a high school student, I made rhymes to remember the elements by group from the periodic table...but that was in Bengali...what did you do?
My chemistry teacher taught the rhyme:
Ken Napolean Caught Mr Albert's Zebra, for P. C. Harry's Aggravated Aunt.
This was the order of the electonegativities for common metals.
K,Na,Ca,Mg,Al,Zn,Fe,Pb,Co,Hg,Ag,Au
(I'm not sure about some of them now).
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Answer to:
Have you ever wondered how big is the universe? I usualy do it when im slightly drunk and out in the garden... it fries my brain, i mean everything has to end and can only be so big? what do you think?
The current best theories depend on 'cosmic inflation'.
This theory suggests that the universe in the first tiny fraction of a second doubled in size many many times.
It grew so fast that most of the universe is so far away that light leaving it will never reach us.
For that reason, science usually confines itself to the 'observable universe' which is that part of...
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Answer to:
Is there really a 50-50 chance in anything? Or is there some factor that sways toward one side?
How would we know?
There is no way you can measure probability to reasonably accurate values in real life without doing the experiments.
If you flip a coin a million times, the theoretical chances that it lands on heads exactly 500,000 times are actually very very very small. In real life, it is far more likely that you will get either more heads, or more tails.
Does this mean the coin...
Answer to:
Given the Zeta function Z(s)= the summation of (1/(n^s) n=1 one to infinity and s is a complex number of the form a+bi, how would you begin to solve the equation Z(s)=0
Is this a trick question? I tell you the exact solutions and you win the million dollar prize for solving the Riemann hypothesis?
You can get approximate solutions by using numerical techniques. A crude idea: pick a complex number where you think there is a zero, evaluate the zeta function at a couple of points near that number, and see which way you have to go to reduce the value of the...
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Answer to:
What is the Diameter and circumference of a HALF circle with the area of 16 sq ft?
Diameter and circumference of a HALF circle with the area of 16 sq ft?
Simple.
If HALF the circle is 16 sq ft, then the whole circle is 32 sq ft
Find the diameter and circumference of that.
Formula:
area = pi r^2 OR C^2/(4 pi)
circumference = 2 pi r OR pi d
Answer to:
How do you get the exact value of cos240? pls help! test tomorrow!!
It helps to know the shape of the cos graph.
cos 0 = 1 at the top of a hill
it then slopes down to cos 90 = 0
then cos 180 = -1 at the bottom of a valley
then up to cos 270 = 0
and back up to the top of the hill at cos 360 = 1
The curve is symmetrical about 0 and about 180 and the part from 180-270 is the negative of the part from 0-90
240 in the region where the cosine is...
Answer to:
I am doing polynomial equations and I am stuck on this problem. X to the 6 power =117694 . I need to find all values and solve for x.
This is a sixth degree polynomial and a sixth degree polynomial has six solutions in the space of complex numbers.
In the space of positive integers:
7^6 = 117649
so x=7 is a solution if you mistyped the question.
If not, then x=(117694)^(1/6) will give you a positive real solution.
In windows calculator, select "scientific" from the menu, and type 117694Y(1/6)= (or just...
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Answer to:
When you change 33 inches to feet ,how can you easily tell if your answer will be an improper fraction?
You can write the answer as 33/12 feet or as 2 feet and 9 inches or as 2 and 3/4 feet.
33/12 is an improper fraction.
If you do it that way, you'll always get an improper fraction if:
1) You didn't get a whole number of feet AND
2) You started with at least one foots worth of inches.
Answer to:
I know the answer, but not how to get there. I have 4x-12y=0 and 9y^2-12x=0 and I'm solving for x and y. The answer is (12,4) according to mymathlab, but I forget how to get there. Anybody remember this stuff?
4x - 12y = 0
9y^2 - 12x = 0
These are simultaneous equations where one of the equations is linear and one is quadratic. You can solve by substituting for the linear in the quadratic, giving you a quadratic.
So 12x = 36y from the linear equation.
Substitute in the second equation:
9y^2 - 36 y = 0
factor:
9y (y - 4) = 0
Either 9y = 0, leading to x=0
or y=4 leading to x=12.
...
Answer to:
How many grams of oxygen is released on complete combustion of potassium chlorate 2KCLO3>2KCL+302
From your equation, 3 moles of O2 are generated for every 2 moles of KClO3
The answer you want is input grams divided by molar mass of potassium chlorate to get input moles and then multiplied by 1.5 to get moles of oxygen and then multiplied by molar mass of oxygen gas, to get the answer in grams.
EDIT:
It isn't possible to give the complete working because you haven't given...
Answer to:
The atoms that constitute your body are mostly empty space, and structures such as the chair you are sitting on are composed of atoms that are also mostly empty space. So why don’t we fall through the chair?
Imagine a golf ball.
imagine you have a handful of pencil sized bar magnets.
Attach the north poles to the golf ball so it looks like a spiny creature.
Make lots of these 'atoms'.
As you push these 'atoms' together the south poles on the end of the spines repel, so it is difficult tto push them together. If you push them far hard though, the spines push through the...
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Answer to:
Calculate the no of moles in 856 grams of glucose (C6 H12 06)
You need the 'molar mass' of glucose in grams.
It is also called the 'atomic mass' or 'atomic weight'.
You should have been told somewhere what the molar mass of glucose is.
You can look up glucose, or any other chemical, on wikipedia and it will tell you the molar mass somewhere in the large box at the top right.
If you don't have access to wikipedia,...
Answer to:
For i = , if 3i (2 + 5i) = x + 6i, then x =?
3i (2 + 5i) = x + 6i
distribute the left hand side:
3i (2) + 3i (5i) = x + 6i
6i + 15i^2 = x + 6i
15 i^2 = x
but i^2 = -1
so now:
-15 = x
Answer to:
Use mathematical induction to prove that the statement is true for every positive integer n. (1-1/2) (1-1/3) ...(1-1/n+1) = 1/n+1
Base case, put n=1
(1-(1/2)) = 1/(n+1) works.
Now assume the equation is true for values of n up to N.
If you can use those facts to prove it for N+1 then that
proves it for all N.
The N+1 example looks like:
(1-(1/2))(1 - (1/3))...(1 - (1/(N+1)) (1 - 1/(N+2)) = 1/(N+2)
According to the equation in the question, which we assume to be true when n=N, we know what the first N factors...
Answer to:
Okay so this is probably stupid but I am confused and getting stressed. I am working on my Algebra for class tomorrow. It says "find the unknown in each equation". Here is one of the equations logx(small and to the bottom)49=2. What is exactly the unknown
When written in words, your equation says:
The logarithm to base x of 49 is 2
The unknown is the symbol x.
logarithms are numbers which are the powers of a base.
I'll try to explain:
If the base is 10,
the logarithm to base 10 of 100 is 2, because 10^2 = 100
The logarithm to base 10 of 1000 is 3, because 10^3 = 1000
The logarithm to base 10 of 10000 is 4.
The logarithm to...
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Answer to:
Can 'the other way round' mean the reversal of digits as well as the revfersal of situations? One example of the former is Speak & Maths is more appropriate at 12 than the other way round.
Example: "It's forty six but the other way round"
Other way around how? It's not quite clear which other way round: does it mean upside-down? Mirror image?
Better to say something like "like the number forty six but with the digits in reverse order"
Answer to:
Did the Proclaimers' hit Letter From America make the charts in America?
"Letter from America" never made the charts as a single in the US.
However, "I'm Gonna Be" by the Proclaimers reached 3rd on the Billboard Hot 100.
Answer to:
How come ITV don't seem to show any good quality children's programmes like Clapperboard and A Handful of Songs any more? I used to like them but both these programmes have long since been axed. Any ideas why?
Children (and adults) of today seem to have less patience than they did when the TV programmes you and I used to watch were on TV.
I think they would not be satisfied with slow moving programmes any more.
Answer to:
What is the Boolean simplification?(not a) and (not b) and (not c) and (not d) or a and (not b) and (not d) or (not a) and (not b) and c and (not d) or a and b and c or b and c and d or (not a) and b and c and (not d)
You can do these most easily with a carroll diagram.
Each phrase separated by 'or' makes a rectangle on the carroll diagram. You shade in all the rectangles and then make the resulting shape with the largest overlapping rectangles that you can.
But AB's fixed width font stuff doesn't work last time I tried, so here's another way:
The six phrases connected by...
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Answer to:
What are the three main branches of mathematics?
There are only two main branches: pure and applied.
Where did you get the idea there were three?
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Answer to:
How do you find the derivative of e^xy?
The derivative of e^A is e^A times the derivative of A.
If you're deriving wrt t you'd get
e^(xy) (x' y + x y')
where x' and y' are the derivatives wrt t of x and y
and I used the product rule to differentiate xy.
Answer to:
One endpoint of a line segment is (8,1) and its midpoint is (3,7) find the often endpoint
And by 'often' you mean 'other'.
The distance from the start to the midpoint is the same as the distance from the midpoint to the end.
It's -5 units in x from 8 to 3, so another 5 units takes you to -2.
Same idea for y.
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Answer to:
Why did my parents think telling them the # of letters in a certain word/phrase/name cute and amusing at 4, 5, 6, 7 or 8 but old hat by the time I was 20?
A four year old might do it to impress his parents, but
it's not a difficult task for a twenty year old. It might make him look stupid instead of clever.
Answer to:
What is the value of 'x' when (sinx)*5+(cosx)*3=1?
This can be solved with the half angle formulae.
sin x = (2t)/(1+t^2) where t is 'tan of the half angle'
cos x = (1-t^2)/(1+t^2)
so you get
10t + 3 - 3 t^2 = 1 + t^2
4 t^2 - 10 t - 2 = 0
2 t^2 - 5 t - 1 = 0
t= (5 +/- sqrt(33))/4
t= 2.686 or -0.186
possibilities for x/2 = 69.5 degrees + some multiple of 180
or x/2 = -10.5 degrees + some multiple of 180
x = (139 degrees...
Answer to:
If a country had a population of 127 million and 50000 guns, how many guns would that be per 100 people and how do you figure that out?
50,000 guns per 127 million people
divide by 127:
393.7 guns per 1 million people.
divide by 10 ...
39.37 guns per 100 thousand people
3.937 guns per 10 thousand people
0.3937 guns per thousand people
0.03937 guns per 100 people
Answer to:
I am thinking of a three-digit number. If you subtract 7 from it, the result is divisible by 7; if 8, the result is divisible by 8; if 9, the result is divisible by 9. What is the number?
Four facts:
(x-7) is divisible by 7
(x-8) is divisible by 8
(x-9) is divisible by 9
x is a three digit number
If a number k is divisible by 7, then so is k+7
if x-7 is divisible by 7 then so is x.
So the four facts are the same as:
x is divisble by 7, 8 and 9 and is a three digit number.
The lowest common multiple of 7,8 and 9 is 504 which leads to the new fact:
x is...
Answer to:
What is the name of the river that flows through Oxford in England?
It is really the Thames, but as it passes through Oxford it is often known as the Isis.
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Answer to:
On what river would you find the thousand islands?
The St. Lawrence River
Answer to:
What is the name of the space telescope that will replace Hubble in 2011?
The James Webb Space Telescope, which is the successor to Hubble, is scheduled to be launched in 2014
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Answer to:
What were Buzz Aldrin's first words he spoke after stepping on the surface of the Moon?
From http://www.hq.nasa.gov/alsj/a11/a11.step.html
[Buzz jumps back down to the footpad.]
109:43:16 Aldrin: Beautiful view!
109:43:18 Armstrong: Isn't that something! Magnificent sight out here.
109:43:24 Aldrin: Magnificent desolation. (Long Pause)
[Still holding on to the ladder with both hands, Buzz hops backwards onto the surface. After a brief moment, he turns...
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Answer to:
Who designed the Saturn V rocket that made it possible to go to the moon?
The Marshall Space Flight Center under the guidance of
Dr. Wernher Magnus Maximilian Freiherr von Braun.
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Answer to:
Did anyone see Ben Steins movie Expelled? Did that not carry any weight with people who believe in evolution?
I read this review:
http://www.scientificamerican.com/article.cfm?id=ben-steins-expelled-review-john-rennie
I'm getting the impression that the movie does not hold much weight with those who understand that evolution is a fact.
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Answer to:
What are fairies weak against? you know, like werewolves hate silver.
alcohol. Apparently.
Answer to:
Which factorial has 30 zeros at the end?
You get a zero whenever a 2 and a 5 come together to make a factor of ten.
Since factorials have loads of factors of 2 it depends on the factors of 5 which will come from
5, 30,55,80,105 (1 zero each)
10,35,60,85,110 (1 zero each)
15,40,65,90,115 (1 zero each)
20,45,70,95,120 (1 zero each)
25,50,75,100 (2 zeros each)
That's 28 zeros.
Next comes:
125 which has three zeros making 31...
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Answer to:
A car is going 10 mph. The driver hits the brakes. The car travels 3 feet after the brakes are applied. A while later, the same car is going 20 mph. The driver hits the brakes. How far does the car go after the brakes are applied?
The distance it takes to brake is proportional to the kinetic energy of the car.
The kinetic energy is proportional to the square of the speed.
There is 4 times as much energy at 20mph as at 10mph.
Therefore it will take four times further to stop = 12 feet.
Answer to:
If it takes 8 men, 12 days to repair 60 cabinets, how many days can 1 man repairs 60 cabinets? with solution please
The way to do these is to write out the sentence with the thing you want to know (days) on the right:
To repair 60 cabinets, 8 men take 12 days.
Now change one of the left two figures and adjust the right figure to match. You have to think each time whether the number on the right goes up or down.
Eventually, need to end up with 60 cabinets and 1 man as the two figures on the left.
...
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Answer to:
Out of ten questions with 4 answer choices each, what is the probability of 6 successful answers with random selection?
This is the binomial distribution.
p = 0.25 ( 1 in 4)
q = 0.75
n = 10 (trials/questions)
i = 6 (number right)
and the probability you are looking for is
p(answers = 6) = nCi p^i q^(n-i)
where nCi is the binomial coefficient.
btw 10C6 = (10*9*8*7*6*5)/(6*5*4*3*2*1)
You should also work out the result for i=7, i=8, i=9 and i=10 and add them on, since you will certainly have...
Answer to:
Why is it called "Maths" in Britain, yet it's "Math" in America?
Because Americans leave off the s!
British probably prefer to leave the abbreviation of the plural "Mathematics" as the plural "Maths" instead of the mass noun "Math" - where did that one come from?
Answer to:
Why does 1 + 1 = 2?
1+1 is meaning of 2.
We just use 2 to mean 1+1.
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Answer to:
A carnival clown rides a motorcycle down a ramp and around a loop-the-loop. If the loop has a radius of 18m, what is the slowest speed the rider can have at the tope of the loop and avoid falling? (At this slowest speed, at the top of the loop, the clown'
The acceleration experienced by an object travelling in a circle is given by v^2/r
If the motorcycle is not to fall, he must be forced upwards no less than the amount gravity is pulling him down.
So he wants v^2/r to be no less than g
v^2 no less than rg
v^2 no less than 18m x 9.8m/s^2
v^2 no less than 176.4 m^2/s^2
v no less than 13.28 m/s (29.7 mph)
Answer to:
From where does limit concept comes from ? why we always take lim h tends to zero?
We understand rational numbers: 1/2, 6/7, 12/3 and so on.
But what about other real numbers like the value of sqrt(2) and pi?
We can never write down all the digits, so how can the concept of such numbers be made to make consistent sense?
How can we ever be certain that two real numbers are the same?
The answer comes in defining real numbers as the limit of a sum. This makes a lot...
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Answer to:
Do you think there is a need/use for the Fibonacci numbers in everyday?
Well 8 is a Fibonacci number, and I occasionally use the number 8, so yes.
But I know that's not what you meant.
Is there a use for the sequence? The sequence does come up all the time in unusual ways: the "rings" around a pine code make fibonacci numbers, or the seeds in a sunflower.
But I use a lot of advanced math in my job, and I don't remember every having to use...
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Answer to:
Does 1+1 really equill 2 or can it be mathmatically proven elsewise?
1+1 is often used as the definition of what 2 is.
Mathematics isn't absolute - if you define your symbols carefully, you can assign any meaning you like to them.
If I define 2 as 1+1+1, then 1+1 is not equal to 2.
You may have seen a proof that uses the usual definitions for arithmetic, but some how ends with 1+1 = 3 or some other nonsensical result. The proof probably...
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Answer to:
Solve for x: x^6-108x^2-46656=0
This is a cubic in x^2
Some ways to solve cubics exactly:
by guessing a solution and dividing,
by using an incredibly complicated formula
by http://www.1728.com/cubic.htm
The website also shows you how to do it with the formula.
There are also methods to get approximate solutions such as by graphing or using Newton Raphson.
Once you have a solution for D = x^2,
then...
Answer to:
You already lost 12 times on a slot machine that has a payout rate of 96 cents on the dollar and the probability to win on the first run is 1%. What is the probability that you will win the 13th time? (10 pts.) A. 1.013% B. 96% C. 1% D. Not enough informa
I'd say not enough information, but I doubt that's the answer that gets you 10 points.
The payout rate doesn't really tell you anything: you can get any payout rate you like just by adjusting the size of the winnings.
The problem is, what was the probability to win on the 2nd run? It could depend on the slot machine.
If this was a dice, the probability of getting a winning...
Answer to:
How can i find the number of ways in which a shopkepper can make $12,using 80 coins which are 50c,20c and 5c coins only,using at least one of each coin?I've been trying to work it out for weeks,can anybody help me?
You want 1200c
Let the number of 50c coins be a
Let the number of 20c coins be b (sure about 20c?)
Let the number of 5c coins be c
You need 50a + 20b + 5c = 1200
divde by 5:
10a + 4b + c = 240
You also know that a+b+c = 80
Subtracting the two equations:
9a +3b = 160
The left side is divisibe by 3 but the right side is not.
Therefore there can be no solution that makes this work.
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Answer to:
As we know, protons attract electrons. so in the atom of a substance why do the electrons keep revolving rather than being attracted to the protons present in the nucleus?
They are attracted to the protons in the nucleus, same as the Moon is attracted to the Earth. But the Moon keeps moving too.
The attracting keeps them from moving too far.
(p.s. for QM freaks: Even in QM, we talk of a potential well)
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Answer to:
Eng question >1,2,6,42,1809,_________?
1*1+1 = 2
2*2+2 = 6
6*6+6 = 42
42*42+42 = 1809 ...
... well it does if the screw came loose on the 6 and it rotated.
You did say it was an engineering question...
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Answer to:
Is it possible to "knock" the Earth out of its orbit around the Sun (or any planet or satellite)?
Yes, in theory.
If a large enough object came close to Earth (or any planet or satellite) it would be gravitationally deflected and could end in a different orbit, or escape the solar system, or plunge into the Sun.
But nothing like this has happened to the Earth in our first 4.6 billion years, and isn't going to happen except in a movie.
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Answer to:
If you have a solute of Ca(HCO3)2 and a solvent of H2O , what would you see(have) in the solution? Don't need amts just what does it break down into.
From wikipedia:
"Calcium bicarbonate (Ca(HCO3)2), also called calcium hydrogen carbonate, does not refer to a known solid compound; it exists only in aqueous solution containing the ions calcium [Ca++], dissolved carbon dioxide [CO2], bicarbonate [HCO3–], and carbonate [CO3-–]. "
Answer to:
If something as small as a a rocket ship can escape the earth's gravitational pull, why doesn't the moon?
A "rocket ship" which plans to leave earth, as opposed to one going into orbit like the moon does, typically has to use up several times its own mass in fuel to escape.
Strap a similar proportion of rockets and fuel to the moon : lets say 200 trillion tons of fuel, and the Moon could escape too!
Answer to:
What time zone are you in?
BST
:)
Answer to:
It's 2:45. Do YOU say, "quarter BEFORE 3," "quarter TO 3," "quarter OF 3," "quarter 'TIL 3," or how do you say that time, in your section of the USA (assuming you are in the USA)? Each region of the USA has its own way, right?
"Quarter to".
But I'm in the fifty-first state.
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Answer to:
What would you call a half bigfoot half werewolf thing?
Sir
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Answer to:
What is your favourite movie you think i`ve never heard of?
Dark star, maybe.
I'm presuming you've heard of a lot of movies though. My favorite movie you have heard of is Pulp Fiction - I think it is an accidental masterpiece, and suits my AB name. I think Tarantino lost most of the plot, literally, with his later movies.
Answer to:
Why is the minimum number of bars on an abacus 9?
It isn't.
Nor is it even the minimum number of beads on a bar.
Some abacusses have nine beads per bar, but some have alternately 1 and 4 (or 2 and 5).
I checked the first page of http://images.google.com/images?q=abacus
and I got this:
1 very long abacus many bars of 2 and 5 beads.
4 abacuses with 13 bars of 2 and 5 beads.
2 abacuses with 12 bars of 2 and 5 beads.
1 abacus...
Answer to:
A car traveling at 70 kilometers per hours travels how many meters per minute?
70 kilometers per hour.
Each kilometer is a 1000 meters.
70,000 meters per hour.
You can go sixty times as far in an hour, as you can in a minute.
You can go one sixtieth as far in a minute as you can in an hour.
(1/60) 70,000 meters per minute
= 7,000/6
= 3,500/3
= 1166 and two-thirds meters per minute.
Answer to:
Evaluate 3x^0 and (3x)^0 when x is not 0. Are the results different?
If A is not 0 then A^0 = 1 whatever A is.
In 3 x^0,
which means (3 multiplied by x^0),
I deduce that x^0 = 1
so substitute 1 for x^0
and I get (3 multiplied by 1)
In (3x)^0, I deduce that (3x)^0 = 1 (I put A = 3x)
I get 1.
Answer to:
Is every mathematical equation considered to be a 'proof'?
A proof is a sequence of true statements each of which follow from previous statements, or from "axioms", following rules of inference.
An axiom is a statement taken to be true to start things off.
Now in one system of math, a = a is an axiom, saying that the symbol 'a' is equal to the symbol 'a'.
In this system there is a rule that says you can...
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Answer to:
What does the definite integral of a vector function actually represent? Is it the total area of the surface spanned from the origin to the vector-point across the parameterized interval?
It depends what you integrate it with respect to.
Acceleration is a vector.
Integrate it with respect to time, you get velocity.
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Answer to:
In mathematics of combinations,is 1234 = 4321?
In a rough and ready kind of way.
In a more accurate way:
{1,2,3,4} = {4,3,2,1}
Answer to:
Does it bother you that 1/3x3=1 and .33`x3=.99` but 1/3=.33`?
By using the backquote, you are indicating a sequence which continues forever: so .33` = .333` and so on.
From your question I can reason that:
0.99` = 1.0
which happens to be absolutely true.
These numbers are "real" numbers. What exactly *is* a real number? If you knew that you'd be able to test if 0.99` = 1.0
Real numbers turn out to be far more complicated...
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Answer to:
1,11,21,1211,111221,312211,.......... find common difference of this Arithematic progression.
If this was an arithmetic progression, then each difference between adjacent terms would be the same.
11-1 = 10
21-11 = 10 ok so far
1211-21 =1190 oops.
Not an arithmetic sequence.
This sequence is called the look-and-say sequence.
start with a 1.
that's 'one 1' = 11
11 is 'two 1s' = 21
21 is 'one 2 and one 1' = 1211
etc.
Answer to:
Of the 216 players on major league soccer rosters, 80.1% are U.S. citizens. If three players are selected at random for an exhibition, what is the probability that all are U.S. citizens
80.1% of 216 = just over 173, so it must be 173 players who are US citizens.
There are (173 choose 3) ways of choosing 3 US citizens.
But there are (216 choose 3) ways of choosing 3 players.
Probability of picking 3 US citizens = (173 choose 3)/(216 choose 3)
216 choose 3 = (216*215*214)/(3*2*1)
173 choose 3 = (173*172*171)/(3*2*1)
(173 choose 3)/(216 choose 3) =...
Answer to:
88% of American children are covered by some type of health insurance. If four children areselected at random, what is the probability that none are covered?
If 88% are. 12% = 12/100 aren't.
Probability of picking four that aren't = (12/100)times(12/100)times(12/100)times(12/100)
Answer to:
Can someone please help me solve this equation by factoring? x^3+8x^2+15x=0
Factorizing trinomials, like this one, I found the hardest thing there is in math. It really gets easier after that. This one's not so hard though:
Each of your terms has a factor of x, so that's the first step:
(x)(x^2 + 8x + 15) = 0
To factor the second bracket, you are looking for something like
(x + a)(x + b)
Because 15 is positive, it tells you that a and b have the same...
Answer to:
What is the measure angle of abc
The question probably said "what is the measure of angle abc?"
This "measure" thing is really old fashioned, so I wonder why it keeps turning up here.
Today we would say "what is angle abc?" or "what is the size of angle abc?" or "how big is angle abc?"
Answer to:
A^2-a^2=a^2-a^2 a(a-a)=(a+a)(a-a) a=2a 1=2 tell me reason behind it.
a^2-a^2=a^2-a^2 ... this is obvious and true for all a
a(a-a)=(a+a)(a-a) ... Each side has been factorized in a different way. Each side is still true representation of its previous value, as you can test by putting in values for a, or multiplying out each side.
a=2a .. Each side has been divided by (a-a).
When you divide by an expression, the result is only definitely true if the...
Answer to:
One hundred tickets numbered 1, 2, 3, …, 100 are sold to 100 different people for a drawing. Four different prizes are awarded. How many ways to award prizes if people holding tickets 19, 47 and 73 all win prizes?
Four possible prizes for ticket 19
... for each of those possibilities there are ...
Three possible prizes left for ticket 47
... for each of those possibilities there are ...
Two possible prizes left for ticket 73
... for each of those possibilities there are ...
97 possible tickets left to receive the last prize.
4*3*2*97 = 2328
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Answer to:
Each of the following expressions is equivalent to 3x - 5 + z. Find the value of the missing coefficients.(answers ill write in answers.)
a) x+2y-2z+?x-7y+?z
b) -x+2y-3z+4x+?y+?z
Try thinking of x as Apples, y as Cents and z as Bananas
a) One Apple + Two Cents - 2 Bananas
+ ? apples - 7 Cents + ? Bananas
is the same as:
Three apples - 5 Cents + 1 Bananas.
so the question is: how many apples do you add to one apple to make three apples ... and how many bananas do you need to ensure you have one banana left if two...
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Answer to:
A tramp was walking down a railroad track when he saw a fast express train speeding toward him. Of course, he jumped off the track. But before he jumped, he ran 10 ft towards the train, why?
He was 10ft short of getting out of the train tunnel.
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Answer to:
Simplify (2a^3b^-3c^)^3/ (3a^-1b^-3c^-5)^2
I can't tell you the answer because you missed out part of the question.
But here are some rules to help you:
(A B)^n = (A)^n (B)^n
(A^n)^m = (A)^(n m)
(A / B) = (A) (B)^(-1)
A^n B A^m = B (A)^(n+m)
apply these rules until you cannot do it any more.
Example, to start with, take: (3 a^-1b^-3c^-5)^2
This matches the first rule with A=3 and B=a^-1b^-3c^-5 and n=2
Therefore I...
Answer to:
Are there endless prime numbers?
Yes.
The proof is quite simple.
Suppose you were able to list all prime numbers on a large sheet of paper.
If there are only a finite number of prime numbers, you could multiply them all together and add 1.
When you divide this huge number by any of your prime numbers, you will always get a remainder of 1.
A number greater than 1 which cannot be evenly divided by a smaller...
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Answer to:
Is the number of letters in informal gathering a prime number?
Yes. I think you knew that.
This isn't a question that many will need to know the answer to. AB encourages "helpful" questions whose answers will be useful to many people.
Answer to:
Not homework - just work. I have a biological sample which has a protein value of 19 mg/ml. 5 microliters was used in the assay. The cholesterol value is 3.8 mmol/liter. I need a formula to convert to show mg cholesterol per mg protein.
5 microliters = 0.005 ml = 0.000005 liters.
19 mg of protein per ml
so you have 19 * 0.005 mg of protein = 0.095 mg
3.8 mmol of cholesterol per liter.
so you have 3.8 * 0.000005 mmol = 0.000019 mmol
a mole of cholesterol weighs 386.65 g
(see http://en.wikipedia.org/wiki/Cholesterol top right)
a mmol (millimole) weighs 386.65 mg (milligrams)
0.000019 mmol is 0.000019 * 386.65...
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Answer to:
Need help solving the following: for the given function, find f(x-h)-f(x)/h
You have a function f(x) = some_formula_including_one_or_more_x
To find f(something) just put (something) in place of each x in the formula. Then simplify it.
For instance if f(x) = x^2
Your formula (f(x-h)-f(x))/h becomes ((x-h)^2 - (x)^2)/h
= -2x + h
This answer may be closer to what you actually wanted:
http://www.answerbag.com/a_view/7026680
Answer to:
Your task is to complete a flow chart to be used for factoring expressions. Use a word document then save and submit in an .rtf format. This flow-chart will: list all of the different factoring techniques from this activity, give a minimum of one example
No, that's *your* task.
There is no set way to factorize expressions so
the flowchart you come up with depends on what you were taught.
How were you taught to factorize expressions?
Answer to:
Given a 12" by 12" square sheet of paper, cut it (not necessarily straight) into two parts that can be rearranged to form a rectangle that is 9" by 16".
Cut a staircase, where each step is three inches high and four inches long.
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Answer to:
How do i write the following numbers in base 5: 13,27,80,190?
In base ten the digits stand for:
thousands (10*10*10)
hundreds (10*10)
tens (10)
units (1)
each digit is less than 10.
In base five the digits stand for:
125's (5*5*5)
25's (5*5)
5's (5)
units (1)
each digit is less than 5.
So for 13 you look for digits cd where 5c + d = 13
For 190 you are looking for digits abcd where 125a+25b+5c+d=190
in both cases the...
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Answer to:
Students are taking a ten question multiple chioce test with a .20 chance of getting each question right what is the mean(probability distribution) if they guessed on all ten?
This is an example of the binomial distribution.
n = number of events = 10
p = probability of event = 1 in 5 or 0.2
q = 1-p by definition = 0.8
Mean = np
Variance = npq
std deviation = square root of variance by definition.
Answer to:
Do you think science or math is more important?
Math, because you can't interpret the results of your science without math. Science is written in math.
Even a simple experiment needs statistics to measure whether the result was significant, or just accidental.
Answer to:
Mathematician Johann von Neumann said, "In mathematics you don't understand things. You just get used to them." Is that your experience when you get past simple arithmetic?
No, I went quite a long way in math, and it was the other way around. The only things I could get my head round were those where I had some mental picture which allowed me to understand it on some level. I can't say I got used to the rest at all!
Fortunately, I was good at mental pictures!
Complex variable and graph theory were my favorite subjects, both of those involve drawing lots...
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Answer to:
What is the first word that springs to mind containing 3 letters?
I thought 'two'.
Why not 'one'?!
Answer to:
When looking at the graph of the equation, please explain the meaning of the right and left bound
left bound = the largest value of x which lies to the left (less than or equal) of all points on the graph.
right bound = the smallest value of x which lies to the right (greater than or equal) of all points on the graph.
Similar to
upper bound: smallest value of y which lies above (greater or equal) of all points on the graph.
Answer to:
How to differentiate x^(1/3) by using lim┬(h→0)〖(f(x+h)-f(x))/h)〗Please show the steps. I know the answer if I use the Power Rule, but I need to know how to do it manually.
You need to somehow find a reasonably good approximation for f(x+h)
In this case a reasonably good approximation for (x+h)^(1/3)
Here's one way:
(x+h)^(1/3) = (x*(1+(h/x)))^(1/3) = x^(1/3) * (1+(h/x))^(1/3)
(1+(h/x))^(1/3) can be approximated using the binomial expansion:
1 + (1/3)(h/x) + (1/3)((1/3)-1)(h/x)^2/2! + ...
So (f(x+h)-f(x))/h ~= (1/3) (h/x) x^(1/3) / h
= (1/3)...
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Answer to:
What is the square root of 12 times the square root of 6?
It is the same as square root of 72, but that kind of misses the point.
12 has a 6 in it already.
sqrt(12) * sqrt(6)
= sqrt(2*6) * sqrt(6)
= sqrt(2) * sqrt(6) * sqrt(6)
= sqrt(2)*6
Answer to:
A car moves at 20 mph from A to B and at 30 mph on the way back. What is the average speed? (10 pts.) A. 25 mph B. 24 mph C. 26 mph D. Infinity
speeds have to be averaged over equal times, not equal distances.
If you did it over distances you'd get 25mph. The car was faster on the way back, so took less time getting back, so if you average over an equal times, the faster speed will have less time to "influence" the average than the slower one. So the result will be slower than 25mph.
If you want to work it out,...
Answer to:
What is the value of (2(x+y)^2)/(2(x-y)^2), if xy=1
Greater than one.
The more different x and y, the closer to one.
If x and y are close, then the value is very large.
Answer to:
Did you use a Calculator today?
Just once. To check the actual value of 10^0.1
If you follow questions in the math category, you might know why.
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Answer to:
1444,1446,1464,1466,1`644,1646,1664,1666 What do these numbers have in common
You listed all possibilities for four digit numbers beginning with 1 and continuing using only the digits 4 or 6.
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Answer to:
Where are phospholipids normally found in a prokaryotic cell?
wikipedia is your friend.
phospholipids have two sides, one water loving, one water hating. Put them in a watery environment (like an organism) and the water hating sides stick back to back forming a membrane...
The cell wall.
Answer to:
Do you think that a chimpanzee and a wolf would make good companions?
No. A chimpanzee is just another primate, like humans. And wolves barely tolerate humans.
A chimpanzee would not know what humans have learned about wolves and would not even do as well.
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Answer to:
A machine that could run itself, and provide extra power,can not work according to physics. but the truth is, no one really knows ?. when a machine is pruduced, people will say, we have just taken physics further. or are we waisting our time looking ?.
The trouble is, physics holds together rather too well...
The laws of thermodynamics follow from the statistical behaviour of particles obeying particle theory.
The beaviour of particles in ordinary scenarios is ridiculously well understood. I mean the predictions of the theory in ordinary scenarios are accurate down to to the last place they can be measured by the most sensitive...
Answer to:
Why is the derivative of y=(1-2x)^65=-130(1-2x)^64 and not 65(1-2x)^64?
Because of the chain rule.
Say 1-2x is A.
Then y = A^65
so dy/dA = 65 A^64
like you said.
But we want to derive with respect to x not A!
So use the chain rule: dy/dx = dy/dA times dA/dx
The 'dA' sort-of-cancels.
dA/dx = the derivative of 1-2x which is -2
so dy/dx = 65 A^64 times -2
= -130 A^64
= -130(1-2x)^64
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Answer to:
I have a flat drive pulley with 22mm dia. and 10mm dia. cylinders. I want to turn that to a 60:1 ratio with maximum pulley size of 98mm and minimum size of 15mm dia. Can use a double reduction if required. How do I work out the sizes of pulleys required?
I'm not quite sure what you want.
You can't do it if you want to keep the 22 and the 10 and just add two more cylinders.
If you can replace the 22 and the 10 then you still can't do it with four cylinders:
98/15 is under 6.6.
Two pairs gives a ratio less than 6.6*6.6 which is less than 45.
Three pairs is ample:
60 = 3*4*5 = (45/15)*(60/15)*(75/15)
I can't do it...
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Answer to:
Will you please give a hand on this 0.5Q3-9Q2-180=0 what will be the value of Q?
0.5 Q^3 - 9 Q^2 - 180 = 0
or, getting rid of the fraction:
Q^3 - 18 Q^2 - 360 = 0
cubic equations can be solved, but unless you can guess one of the solutions, the method is very tedious.
Too tedious slow and error prone for a student to be expected to do it.
This particular cubic has no simple solution, so I think you would need the tedious method.
The site
...
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Answer to:
How many (5-card) hands are there that give you a full house?
example full house:
3 of spades
3 of hearts
3 of diamonds
A of spades
A of hearts
There are 13 choices to use where I wrote '3'
In my example there is no 3 of hearts. There are four choices for the missing suit here.
There are 12 choices to use where I wrote 'A'
(can't choose 3 again unless your deck has five suits!)
There are six ways to pick two...
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Answer to:
How do I put this equation into the quadratic formula?
(3x)²-12(3x)+27=0
Two different ways.
The quadratic formula X=(-b +/- sqrt(b^2-4ac))/(2a)
finds a solution for a X^2 + b X +c
I've used a capital X to make it clear it doesn't have to be the same x as is in your question.
So I can put X = 3x, a=1, b=-12, c=27
which gives 3x = (12 +/-sqrt(144 - 4*1*27))/(2)
3x = (12 +/- sqrt(36))/2
3x = 6 +/- 3
x = 2 +/- 1
x=1 or x=3
OR I can put...
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Answer to:
Finding the area of a square that is 7 7/9 on a side
7 7/9 = 7 + 7/9 = 7/1 + 7/9 = 63/9 + 7/9 = 70/9
(70/9) squared = (70 squared)/(9 squared) = 4900/81
Answer to:
Isosceles trapezoid ABCD has an area of 276 in.squared. if AD=13 inches and DE=12 inches find AB
E????
where's E?
An isoceles trapezoid (which is an isoceles trapezium outside North America), is a four sided figure with two parallel sides and is symmetric.
There are only three degrees of freedom. you can take them to be the lengths of the parallel sides and the distance between them.
You have three fixed numbers which is enough to pin down a specific trapeziod.
If the...
Answer to:
If 'a' is any algebraic number , prove that there exists a positive integer 'n' such that 'na' is an algebraic integer
An algebraic number is a solution of a polynomial with rational coefficients, for example, a value of x which solves "b x^2 + c x + d = 0" where b c and d are rational constants.
An algebraic integer is similar only the constants are integers.
An equation like "b x^2 + c x + d = 0" can be transformed like this:
b n (nx)^2 + c n^2 (nx) + d n^3¸= 0
Each term...
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Answer to:
What is a real number
A rational number is any number which can be written as p/q where p and q are integers.
a real number can be a rational number, or any number that can divide the set of rationals into two halves, where all the rationals in one half are less than all the rationals in the other half.
Example: take the irrational number which is the positive square root of 2.
You can divide rationals into...
Answer to:
Hi, I need to know all the combinations of any four numbers (whole) that are between 1 - 110 that equal 230 when added.
thanks
strugglin
strugglin asked for an excel formula. I'm not good at excel but this combination of formulas seems to work:
First place the starting combination 1,10,109,110 in A1 thru D1
Place =IF(H2,P2,A1) in A2
Place =IF(H2,Q2,K2) in B2
Place =IF(H2,R2,L2) in C2
Place =IF(H2,S2,M2) in D2
Place =AND(SUM(A2:D2)=230,AND(A2<B2,AND(B2<C2,AND(C2<D2,D2<=110)))) in E2
Place...
Answer to:
Hi, I need to know all the combinations of any four numbers (whole) that are between 1 - 110 that equal 230 when added.
thanks
strugglin
There are around 30000 combinations!
There's no easy way to work them out other than trying to list them in increasing order:
Start with a combination beginning with 1.
The remaining numbers must sum to 229. The largest that can be made with two different numbers is 219, so the remaining number must be at least 10.
that gives the first combination as
1,10,109,110
now it gets...
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Answer to:
10x/13 times 39/15x multiply and write in simplified standard form
10x/13 times 39/15x
there are several ways to "cancel" here.
That's when you divide a top number and a bottom number in a product of fractions by a common factor.
These are all the things you could do as a first step:
x cancels on the top and bottom OR
10 cancels with 15 leaving 2 on the top and 3 on the bottom OR
39 cancels with 15 leaving 13 on the top and 5 on the...
Answer to:
The cost of fuel in running an engine is proportional to the square of the speed and is Rs.48 per hour for a speed of 16 mph. Other costs amount to Rs.300 per hour. What is the most economical speed?
fuel cost per hour = k speed^2
48 = k 16^2
k = 48/256 = 3/16
distance = speed * time
for a given distance and speed, time = distance/speed
fuel cost in that time = fuel cost per hour * time
= fuel cost per hour * distance/speed
= k * speed * distance
additional cost = 300 per hour = 300 * distance/speed
total cost = (3/16)*speed*distance + 300*distance/speed
total cost per mile =...
Answer to:
Can lim(x->∞) =∞? I got the question lim(x->∞) (x^2-4x+4)/(x-2) and that's what I got, is this correct or does it mean that the limit does not exist?
Yes your answer is correct, but at the same time in some technical sense this function does not have a limit because it increases without bound.
How can these two apparently contradictory things both be true?
lim(x->inf) f(x) = inf is a shorthand for saying that as x tends to infinity f(x) increases without bound and therefore has no limit!
This shorthand might just be more trouble...
Answer to:
What is the answer?
Use the listing method to represent the following set. {x | x ∈ I, x ≥ 3}
{..., 0, 1, 2, 3}
{3, 4, 5, 6, ...}
{4, 5, 6, 7, ...}
That depends what you mean by 'I'.
I suspect your teacher is confused. If he/she means the set of integers, the standard symbol for that is a Z printed twice so that it looks like a hollow Z.
In ASCII text the symbol is most often denoted ZZ
Instead I is used in math to mean the unit interval.
The ASCII form of the question I think you were asking is:
Use the listing...
Answer to:
True or False. The area under the graph of a binomial distribution with fixed probability increases as the number of trials increase. Why or why not?
It does depend which graph you're talking about.
Assuming you mean the graph of the probability density function, the area under the graph is equivalent to the probability of the events covered happening. If you graph the whole distribution, that's the probability that anything at all happens: i.e. 1.0
All distributions will have that same area, whatever the parameters.
Answer to:
What would be a formula for distribution function B for a binomial experiment that has 35 trials where the probability of success in each trial is .80? What would be the mean and standard deviation for the binomial distribution?
The formula for the binomial distribution is
P(i successes) = nCi p^i q^(n-i)
Where q=1-p and nCi is the binomial coefficient.
You just have to learn this.
In your example, n=35 and p=0.8
The mean and variance of a binomial distribution are np and npq
(and standard deviation is the square root of variance)
You can work this out from first principles, but you're better off...
Answer to:
Would you agree that counting the # of letters in a certain word/phrase/name is a sign of OCD? I would say, from a child of 4, 5, 6, 7 or 8 (or perhaps 9) this is a party trick. Any views on this?
OCD is characterized by repetitive unnecessary behavior which is not useful.
Repeatedly counting the number of letters in words or repeatedly asking a question about it on AB could be symptoms of OCD.
However, OCD is a specific clinical condition.
I suspect that in this specific case, it is a side effect of Asperger's syndrome rather than a symptom of OCD.
Answer to:
You are playing russian roulette by yourself with a 7-chamber revolver. There are 4 bullets in the revolver and the three empty chambers are side-by-side. You pull the trigger and do not get shot. Do you spin the clip or pull the trigger?(Better odds)
Interesting scenario.
Assuming your two choices are the only two available to me and I'm not suicidal ...
Let 1,2,3,4 be the bullets and 5,6,7 be the empty slots.
If I spin the clip I have a 3 in 7 chance of survival.
Otherwise, if I survived the gun must have been in position 5, 6 or 7 and the chamber moved on to position 6, 7, or 1. Two of those are empty so I have a two in...
Answer to:
In what direction is information transmission impossible, the negative temporal direction (i.e. back in time) or the positive temporal direction (i.e. forward in time)? Offer explanations, and bear in mind that the answer may seem counter-intuitive.
It is obvious that information can be carried forward in time.
A buried encyclopedia carries information to the future person who digs it up.
Information cannot be carried through space faster than light will travel.
So the question is can information be carried backwards in time.
The ways that this can happen are the same ways that time travel can happen: through gravitational...
Answer to:
What does this mean? Qadi Zada's(Mathematician) most original work was a computation of sin 1� with remarkable accuracy.
I guess the missing symbol is a 'degree' symbol?
So 1 degrees.
Draw an angle of one degrees. Pick one of the lines and draw a line at right angles to this. You have made a triangle. If you divide the length of the short side opposite the angle by the side opposite the right angle, the hyptoenuse, then you get a fixed ratio called the sine of the angle. This is the same ratio...
Answer to:
This is one for the mathematicians...it is from the comics. Does anyone know if Agnes is right? see my answer for the cartoon.
Here is the comic: http://www.gocomics.com/agnes/2009/06/01/
And the answer is, Agnes is not quite right. The answer is 292. Agnes has counted the dollar itself as being a way of making change for a dollar.
I don't think there's any easy way of doing this puzzle except to break it down like this:
Ways of making 100 cents using 1,5,10 and 25:
using 4 quarters: 1 way
using 3...
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Answer to:
What comes after 9?
Eight hours of boredom.
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Answer to:
What will happen if you get a time machine for a day?{Tell what ever you think}
I would like to visit the future to see what technology is like.
I would make sure to learn which companies are doing well in the next few years so that when I come back I can make a fortune investing on the stock market.
Answer to:
What kind of bond does carbohydrates form?
The bonds in carbohydrates are covalent bonds.
The bonds between carbohydrates are hydrogen "bonds" which are not really bonds at all but electrostatic attraction.
Answer to:
There are 6 balls in green color & 6 balls in red color in a box. What is the probability that same color ball will come out in two chances?
Are you putting the ball back each time? (Drawing with replacement)
If so, then it would be 50/50: same or different, still six balls each way.
But if you take the first ball out of the box, then you will have five of the same color and six of the other color, so the chances will be 5 to 6 or "five elevenths" or about 45% chance of picking the same color again.
Answer to:
Is there a planet X?
Maybe.
Planet X would be the mysterious "tenth" planet. The ninth we all know is really Pluto despite astronomers attempts to demote it.
Nowadays, it would have to be a pretty big object for the tetchy astronmers to count it as a planet and it is still possible that there is a tenth planet which is quite dark and a long way off so we haven't spotted it yet.
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Answer to:
How did you get so smart?
I think I am smart for a primate, partly due to interiting the genes of my fairly smart parents, and partly up to having attentive parents who wanted me to learn.
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Answer to:
Did anyone every scold you for sneezing out loud in a crowded public place?
Maybe. Well you are supposed to cover your mouth and not sneeze on people.
Answer to:
One or Zero, which is a more significant concept?
Personally I think they are pretty well balanced.
Zero is the additive identity.
One is the multiplicative identity.
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Answer to:
Could gamma rays be the dark energy we are looking for?Because the only way we can see these massive explosions is through red shift.
I don't think so, gamma rays carry energy, and energy gravitates: energy and mass are interchangable.
Dark Energy is a bit like negative mass, it accelerates the expansion of the universe rather than the retardation we would expect from the gravity of mass and energy.
Answer to:
Which country / region is the first on which the sun rays would fall?
Millenium Island, Kiribati, in the Pacific Ocean, is where the earliest day begins.
Millenium Island was formerly known as Christmas Island.
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Answer to:
Can someone "please" give me a "specific" (by the way did I mention "specific") reason why the algebraic harmony on EinsteinElectricity.com is wrong?
Here's a very specific answer from a mathematician: There's no such term as "algebraic harmony". It has no well defined meaning.
... and now I've read your page. Your units do not balance.
For a physical equation to make sense, each quantity must be expressed in units, and both sides must balance. If the units are unstated then they must be units from the same...
Answer to:
I know that N and N x N are equipotent but can anyone give me an explicit bijection between these two sets (in either direction)?
By 'N' I know you mean the set of positive integers.
You want a way of turning one integer into two and back without missing any numbers.
Here's one way.
Write the number in decimal. 12345678 say.
This can be split into two numbers by taking every other place:
1357 and 2468.
The numbers are recombined in the same way, accounting for initial zeros, so for instance, 12...
Answer to:
What is the probability of getting a face card (Jack, Queen or King) out of a deck of 52 cards? Now suppose before I handed them to you, I dropped 5 of them. What is the probability now?
Before: probability of the top card of a shuffled deck of cards being one of the twelve face cards is 12/52 = 3/13
Probability is a measure of lack of knowledge. Our lack of knowledge about what the top card is doesn't change when you drop five of them, providing we don't see which ones you dropped.
Therefore the probability of the top card being a face card is exactly the same...
Answer to:
What is the one-millionth term in the sequence 1,2,2,3,3,3,4,4,4,4,5,5,5,5,5,....in which each positive intiger n occurs n times?
The last 1 is at position 1.
The last 2 is at position 3.
The last 3 is at position 6.
The last 4 is at position 10.
etc.
Add any two adjacent positions and you get a square.
Add the position of the last 1 and the last 2 and you get 4 which is 2 squared.
Add the position of the last 2 and the last 3 and you get 9 which is 3 squared.
The last 2 (at position 3) is three positions...
Answer to:
I've been stumbling on these 2 questions
The first: Find the volume for the regular pyramid. The second: Find the lateral area the regular pyramid This is the pyramid spoken of in both questions: http://img206.imageshack.us/img206/3897/regpyramid.jpg
The picture is a regular tetrahedron of side 4.
How to solve.
Draw a diagram of the base triangle.
It's an equilateral triangle. Label the corners A,B,C starting at the lower right and going clockwise.
Draw the center of the triangle, O, and join to each vertex and to the center of each side.
Let the center of the side opposite C be H.
You know AB = 4
AH = HB so you know BH.
...
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Answer to:
If i were to have a roof with a 30 60 90 triangle, the 90 being the roof peak and the bottom side(2a), the left side (a -square root- of 3)and the right side(a). assuming a=3 units how would i figure the distance from the peak to the 2a side? (the bottom)
A nice way is to find the area of the triangle using
Area = half base times height.
Since the (a) side and the (a sqrt(3)) sides are at right angles, you can take one to be the base and the other the height to get
Area = (1/2) (a) (a sqrt(3))
But now if you take the (2a) side to be the base, then you get
Area = (1/2) (2a) h
where h is what you want to know.
The two areas are...
Answer to:
What is the volume of the field, that is bounded by the areas: y = (x-1)², y = 4, z = 0 and z = y
The volme will be the same as a field bounded by the areas: y=x^2, y=4, z=0, z=y
Let x and y be in the paper, with x pointing right and y pointing away. z points out of the paper towards you.
z=0 is the paper itself.
The hard one is z=y, which is a plane through the x axis, which slopes up away from you at an angle of 45 degrees to the paper.
Seen from above the paper:
y=x^2 is a...
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Answer to:
If i have a cylinder thats 66inch in lenght and 44 inch in diamerter how many gallons will it hold??? and if you can explain how to get the answer that be great!!!
The formula, which you just have to know, is
volume = pi r^2 h
r is radius which is half of diameter (22 inches).
So in google
pi * (22 inches)^2 * (66 inches) in gallons
here is the link that does that:
http://www.google.com/search?q=pi+*+%2822+inches%29%5E2+*+%2866+inches%29+in+gallons
If you didn't live in the US you would search for:
pi * (22 inches)^2 * (66 inches) in...
Answer to:
What are the first three entires in the 50th row of Pascal's Triangle? What are the last three entries?
Pascal's triangle is symmetrical, so the last three are the first three in reverse order.
If as is conventional you define the row containing a single 1 as the zeroth row, then the entries on the 50th row are:
50C0, 50C1 and 50C2
9C3 stands for 9 choose 3 and is calculated like this:
9C3 = (9*8*7)/(3*2*1)
50C0 is 1
50C1 is 50/1 = 50
50C2 is (50*49)/(2*1) = 1225
Answer to:
What is the sum of the entries in the 100th row of Pascal's Triangle?
If you define the row with a single 1 as the zeroth row, then the 100th row adds to 2^100 = 1267650600228229401496703205376
If you define the row with a single 1 as the first row, then the 100th row adds to 2^99 = 633825300114114700748351602688
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Answer to:
How long must a simple pendulum be if it is to make exactly one complete vibration per second?
T = 2 pi sqrt(L/g)
L = (T/2pi)^2 g
= (1/6.28)^2 * 9.8
= 0.248 m
(=9.77 inches)
Answer to:
A fisherman notices that wave crests pass the bow of his anchored boat every 3.0s. He measures the distance between two crests to be 7.5m. How fast are the waves traveling? How would I figure this out?
Hint:
If the waves travel 7.5m in 3s, then how far would they travel in 1s?
How many meters per sec would that be?
Answer to:
In geometry, what does sqrt stand for. Like 5sqrt(2)
5 sqrt(2)
means
five times the square root of two.
Answer to:
Explain why the following converges or diverges? 2/1!+2x4/3!+2x4x6/5!+........
The ratio r(n) = a[n]/a[n-1]
= 2n/((2n-2)(2n-1))
The ratio test says if r(n) has a limit < 1, then the series converges.
(If r(n) has a limit greater than 1, then the series diverges, if it equals one, then unknown)
r(n) has a limit of 0
Therefore the series converges (to 3.82ish)
Answer to:
Prove that r/n*nCr=n-1Cr-1 for all integers N>or equal to 2 and 1< or equal to r<or equal to n
Use the definition of nCr,
One possible definition is n!/(r! (n-r)!)
(n! means n factorial means n*(n-1)*(n-2)*...*3*2*1)
So nCr has three parts in this definition.
Changing (n-1)Cr to nCr
changes (n-1)! to n!, which multiplies by n.
Changing 1/(r-1)! to 1/r! divides by r.
(n-r) doesn't change.
Answer to:
A cylinder is inscribed in a right circular cone of height 6 and radius (at the base) equal to 4. What are the dimensions of such a cylinder which has maximum volume?
How to work this out.
tallest possible cylinder is height 6 radius near zero.
shortest cylinder is height near zero, radius 4
So the whole range of possible cylinders from t=0 tallest to t=1 shortest is:
height = 6 + (0-6) t = 6 - 6t
radius = 0 + (4-0) t = 4t
volume = pi r^2 h = pi (16t^2) (6 - 6t)
Differentiate. Solve for t to find possible maxima. Check maxima are maxiuma....
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Answer to:
Cn=(6/5)^n Does this sequence have a limit? If so, what is the limit?
(6/5)^n means each new entry in the sequence is multiplied by (6/5)
Starting at a positive value, each new value increases.
It can only have a limit if there is some ceiling to this process, so that although getting bigger it is bounded above.
Suppose it is bounded above by M, for some positive number M.
Then it certainly doesn't go higher than M.
So there can be no value of...
Answer to:
Tn=1,000,000/n^2 Does this sequence have a limit? If so what is the limit?
Find limit 1/n^2
multiply it by 1000000!
1/n^2 is always positive for positive n.
Suppose limit 1/n^2 is some number K.
Then by the definition of limit, for any given positive eps error value, there exists a number M, for which any n>=M gives a result closer to K than distance eps.
So say I pick K to be the positive number Z, and I pick eps really small. Smaller than Z, so that...
Answer to:
What good reasons do have for giving neg points? I thought neg points were for not good advice or not a clear, good question. Instead I find they are given to people that some AB users don't like. Doesn't that show lack of intigrity?
To iwnit, as far as I am concerned, downrating is for primarily one purpose, when the best answer has been usurped by a stupid unhelpful answer, and uprating isn't enough to fix it.
I might also add a -1 to questions and answers which are intended to annoy, so as to add to the disincentive for doing this.
I think being allowed to give +6 or -5 is unfair. The one person who should be...
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Answer to:
ABC is an isosceles triangle, and AB = AC. D is a point halfway between B and C. AD is the altitude and has a length of 30. What are the lengths of sides AB and BC, and what is the area of the triangle?
Using SOHCAHTOA in each right angled half of the triangle:
AB = AC = 30/cos(A/2)
BD = DC = 30 tan(A/2)
BC = 60 tan(A/2)
area = half the base times the height:
area = 30 tan(A/2) times 30
= 900 tan(A/2)
P.S. tan(45 degrees) is 1
Answer to:
The mean of two numbers is 11. When a third number is included, the mean becomes fifteen. Find the third number?
Sentence 1:
(a+b)/2 = 11
Sentence 2:
(a+b+c)/3 = 15
Eliminate fractions:
a+b = 22
a+b+c = 45
subtract!
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Answer to:
Roll a number cube 20 times If you were to roll a 6 twelve times, would you believe it is a fair number cube? Explain?
Probably not fair.
In 20 rolls you expect a six in about 20/6 rolls = 3.3 rolls
A statistician sets up a test: let the null hypothesis be that the die is fair.
The test will be that the die is not fair, the number of sixes is more than that expected.
Now we set a confidence limit of 95% meaning that 19 times out of twenty the conclusion will be correct.
But it means something simpler too....
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Answer to:
Mark has a piece of string that is 12 inches long. He shapes the string into a rectangle that has a area of 5 square inches. Can Mark make a shpe that has a greater area with the string? If so, what is the area and how did you get the answer?
The largest area you can make with a given perimeter is a circle.
The circle with circumference 12 has radius 6/pi (about 1.9) and has area 36/pi = about 11.4
(using the formula C = 2 pi r and A = pi r^2)
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Answer to:
9 ( A²+ 2AB - B²) -2 ( A² + ab) Simplify the poniminal by using distributive property and show your work. ( Please NOT for homework just understanding)
The distribution property turns
a(b+c) into ab + ac
or
(p+q)r into pr + qr
It is this part you need to get.
It's like saying
five [lots of] (apple + orange) = five apples + five oranges.
9 (A^2 + 2AB - B^2) is 9 A^2 + 18 AB - 9 B^2
2 (A^2 + AB) is 2 A^2 + 2 AB
subtract these:
7 A^2 + 16 AB - 9 B^2
Answer to:
A skydiver is falling governed by mdv/dt = mg - kv^2, where m is mass, g is gravity acceleration, and k>0 is an air resistance constant.
How do I find the analytical solution for v(t) assuming that v(0)=0?
Separate variables:
integral dv / (g - (k/m) v^2) = integral dt
integrate by substitution:
put v = sqrt(mg/k) tanh theta
v^2 = (mg/k) tanh^2 theta
(k/m) v^2 = g tanh^2 theta
g - (k/m)v^2 = g( 1- tanh^2 theta)
dv/(g-(k/m)v^2) = dv/(g(1-tanh^2 theta))
dv/dtheta = sqrt(mg/k) (1 - tanh^2 theta)
dv = sqrt(mg/k) (1 - tanh^2 theta) dtheta
equation becomes:
integral sqrt(mg/k)...
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Answer to:
I need LOGIC number? answer should be between 0-6 | 3 | 4 | 4 | 4 | ? | 1 | 2 | 3 | 4 | 5
There isn't enough info to be certain.
5 is possible so that both groups of five are symmetric about their average central number.
0 is also possible if both groups of five should have an average of 3.
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Answer to:
Classify the triagle by its sides and by its angles. THEN FIND THE MEASURE OF THE 3RD ANGLE. 1. A= 65 DEG, C= 65 DEG, AC= 4 IN
Two of the angles are the same, and since an equilateral triangle has angles of 60 degrees not 65, this is merely an isosceles triangle.
Angles in a triangle add to 180. That will give you the third angle (B).
Answer to:
Please help i need the answer for this: y=(2x^3-x^2+x-2)/x^2 ,find dy/dx?
Differentiation is not hard, just tedious.
You can do it with just these rules:
Let D(A) represent differentiating a formula A wrt x
D(A + B) = D(A) + D(B)
D(A B) = A D(B) + D(A) B
D(A / B) = (D(A) B - A D(B))/B^2
D(x) = 1
D(K) = 0, where K is any formula not containing x.
D(A^n) = n A^(n-1) D(A) where n does not contain x.
Just keep on applying the rules until no D is left.
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Answer to:
What are the next two letters? s e m i t m w q t u f __ __?
Even letters: every fifth letter of the alphabet. Next letter y.
Odd letters: days of week, Next letter s.
If there is another answer to this question by me, please mark this one as nonsense - AB may or may not have lost my original answer.
Answer to:
What are the next two letters? s e m i t m w q t u f __ __?
Every odd placed letter is the first letter of a day of the week.
That leaves e i m q u
e (fgh) i (jkl) m (nop) q (rst) u (vwx) y
That makes the next two letters y and s
Answer to:
A company sells sugar in 750g packages at $1.08 each, or in 600g packages at 84 cents each. State which is more economical price. Be sure to show all the working please?
Depends on how much sugar you want.
If you want 750g of sugar, go for the $1.08 package - it will be cheaper than buying two 600g packages at $1.68
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Answer to:
If 8 is less than twice a number is 48 what is the number
There are too many verbs in your sentence.
Do you mean "If 8 less than twice a number is 48" ?
Let the number be x
If 8 less than twice x is 48, what is x?
If 8 less than 2x is 48, what is x?
If 2x - 8 is 48, what is x?
If 2x is 48 + 8, what is x?
if 2x is 56, what is x?
If x is 28, what is x?
I know!!! I know!!!
Answer to:
A certain number increased by 5 times itself equals 42 find the number
The certain number is x
x + 5x = 42, says the question.
6x = 42
divide both sides by 6.
x = 7
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Answer to:
N^2-n What is the answer to that? Its n squared - n My friend tells me it cant be solved because the - n isnt squared.. I think the answer is "n". Thanks!
Imagine a square of coins of side N.
There are N^2 coins.
Take away N coins. That's one row of N coins.
Now you have a rectangle.
It is N columns by (N-1) rows.
N^2 - N
= N times (N-1) = N(N-1)
Example: N=4
A square of side 4 = 16 coins. A 4 by 4 square.
Take away 4 coins = 12 coins. 4 columns, 3 rows.
12 is bigger than N.
Answer to:
How do I find projective line, if I know two points x1;y1 and x2;y2.
Do you mean the line through two points?
(y-y1)/(y2-y1) = (x-x1)/(x2-x1)
Clearly this equation is linear in x and y, and both sides are zero at (x1,y1) and both are 1 at (x2,y2)
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Answer to:
How do I solve this problem x(x+y)(x+y)
You are probably supposed to distribute it:
x(x+y) = xx+xy
(xx+xy)(x+y) ...
using the rule I learned on AB called 'FOIL'
First (first in each bracket: xx x)
Outer (outer two terms: xx y)
Inner (inner two terms: xy x)
Last (last in each bracket: xy y)
= xxx+xxy + xyx+xyy
which is x^3 + 2x^2 y + x y^2
if multiplication is associative and commutative
But normally if...
Answer to:
I have noticed that in every advertisement of watch, the time shown in watch is 10:10. why?
It is allegedly supposed to resemble a smile, so you think happy thoughts and buy the watch.
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Answer to:
In science, who proposed that 'theory' as used in science differed from 'theory' in the dictionary? And when, if possible.
I think Galileo was the founder of science as we know it today, doing controlled experiments to find out new facts.
The word "theory" as used in science DOES appear in the dictionary, but like many words it has many different meanings, of which the sciency meaning is one.
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Answer to:
If you didn't know the Sun was a great big ball of gas on fire and you saw it for the first time, what would you think?
Well before I found out that the Sun was ball of plasma and gas heated to incandescent by nuclear reactions in its core, I used to think it was a ball of gas on fire.
And before that I guess I thought it was a very hot bright solid object with unknown source of power.
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Answer to:
If light is made of energy particles called "photon" and photon emits energy in the form of light, what makes sense? Is photon emitting its own self?
"photon emits energy in the form of light" does not make sense.
A proton, with an 'r', could emit energy in the form of light (photons).
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Answer to:
If time is relative, does that mean that time on other planets may be slower or faster than time on Earth because we're traveling around the sun at different rates? Would we have to take our rotation round galactic central point into consideration aswell?
Yes, time on Earth is different because we travel round the Sun at different rates, but a bigger effect is gravitational time dilation: Time runs slower at the bottom of a gravity well, like we are. The bigger the gravity well, the slower time runs.
You're only likely to need to know this if you intend to create a GPS system for your new planet. Only very very accurate experiments such...
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Answer to:
What are antimatters and dark matters?
Antimatter particles are just like their matter equivalent but have the opposite charge and spin.
An antimatter particle can collide with a matter particle to be converted into pure energy in the form of photons.
Most stuff is matter, but antimatter is briefly produced in some rare situations, like the decay of some radioactive substances.
Dark matter is an invisible substance that we...
Answer to:
Can we get oxygen cold enough to solidify and if so what colour is it?
Yes you can solidify oxygen. It's sky blue.
The sky is blue, they say, because oxygen molecules scatter blue light.
But this is just a very confused way of saying that oxygen, in large quantities, *is* blue. Which it is.
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Answer to:
When you mix two colours together, is the new colour's wavelength the average of the two starting colours? Higher? Lower?
a) No.
b) No.
c) No.
Every ordinary color is a combination of wavelengths at various frequencies and intensities. Every ordinary color has a spectrum.
When you mix non-coherent light of those colors the intensity of each wavelength is added.
If you add pure blue light of a single wavelength to pure red light of a single wavelength, then you get a color which has two peaks in its...
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Answer to:
If f(x) = x^2 then f(x-1) =?
If f(x) = x^2
then f(x-1) = (x-1)^2
and
f(sin(x)) = (sin(x))^2
f(rabbit) = (rabbit)^2
f(COAT) = (COAT)^2
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Answer to:
How do you figure out what 8x-3x^3 is
In what context?
You can get an idea of what it looks like by drawing a graph.
There is an online grapher here:
http://www.walterzorn.com/grapher/grapher_e.htm
Delete everything in the function box.
Type in 8*x-3*x^3
hit Plot Graph.
Answer to:
How do you solve 8x-3x^3
When you are asked to solve an expression which is not an equation, it means to solve for when the expression is zero.,
8x-3x^3 = 0
You'd solve that by factorizing the expression:
x(8-3x^2)=0
the second factor can be further factorized by using the
difference of squares formula: a^2 - b^2 = (a-b)(a+b)
x(sqrt(8)-sqrt(3)x)(sqrt(8)+sqrt(3)x) = 0
Any one of the three factors...
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Answer to:
Prove the quadratic equation is a solution to ax^2+bx+c=0.
x= -b-{b^2-4ac}
---------------------
2a
x=((-b-(b^2-4ac))/2a)
substitute this in ax^2 + bx + c
What do you get?
Hint: place the three terms over a common denominator of (2a)^2
Answer to:
Consider the system of linear equations ax+by=k cx+dy=l ex+fy=m. Discuss the relative positions of lines ax+by=k cx+dy=l ex+fy=m when: (a) The system has no solutions; (b) The system has exactly one solution; (c) The system has infinitely many solutions.
The solutions are equivalent to where the lines cross or touch.
a) Think about how three lines can avoid touching each other at all.
b) Think about how three lines can cross or touch at one place only.
c) Think about how three lines can touch in an infinite number of places.
Answer to:
What is the physical meaning of the integral of the volume of a sphere. Or to be clearer, if you integrate the volume of a sphere you get an equation with an r^4. What could this mean? Or could it mean nothing at all?
Consider the integral of the area of a circle.
integral of pi r^2 dr
Let's integrate it from r=0 to r=R for some value R.
This is the sum of the areas of lots of discs whose radii start off at zero and increase up to R in a linear fashion.
Create an r axis starting on the table at r=0 and pointing straight up.
Pile the discs on top of each other, with the smallest zero radius...
Answer to:
Which equation represents the line that contains the point (5, 4) and is perpendicular to the line
y = -(1/5)x – 7?
A. y = -(1/5)x + 5
B. y = 5x – 29
C. y = 5x – 21
D. y = 5x – 1
y = mx + b
where m is the slope.
in your equation m = -(1/5)
If two slopes are perpendicular, they multiply to make -1
so a perpendicular slope would be m=5
so looking for y = 5x + something
That eliminates A as a possible answer.
For a line to contain a point, the line equation must be true for that point.
A: 4 = -(1/5)*5 + 5 is true (but we eliminated that)
B: 4 = 5*5 - 29 is...
Answer to:
Write the equation for the translation of y = |x|, 2 units to the right and 11 units down.
These are harder than they look.
So draw a picture of what we want it to look like.
The lowest point is at (x=2,y=-11)
So start with y = -11
and add to this, an amount which starts at zero when x=2 and increases as x moves away from 2.
y = -11 + |x-2|
|x-2| can be throught of as "the distance of x from 2"
|x| is the distance of x from 0
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Answer to:
What equation represents a line parallel to the line x + 2y = 12?
x + 2y = 12 + d
where d is any constant
and preferably d is non-zero to avoid arguments as to whether a line is parallel to itself.
Answer to:
How do you simplify the left hand side of (1-sinx)/(1+sinx) to equal tan^2(45-x/2)
Use the half angle substitution.
Learn these:
sin(x) = 2t/(1+t^2)
cos(x) = (1-t^2)/(1+t^2)
tan(x) = 2t/(1-t^2)
t stands for tan(x/2)
(generally you do everything with t's and convert to tan(x/2) later)
After the substitution you have:
(1+t^2-2t)/(1+t^2+2t)
= ((1-t)/(1+t))^2
This looks a little like the tan(A-B) formula:
tan(A-B) = ((tan A) - (tan B))/(1 + (tan A)(tan B))
...
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Answer to:
A pipe with a 10"3/4 O.D into a 11"15/16 I.D what is the gap all the way around, pipe is centered
The difference is
11" 15/16 - 10" 12/16
= 1"3/16
that accounts for two amounts of gap: one each side.
So, dividing it by two gives you: 19/32nds of an inch.
This is probably even easier to see by just drawing it with a ruler marked in 16ths.
Answer to:
Let f: R----->R be defined by f(x) = x/2x+1 x≠o show that f is (i) one-to-one (ii) Onto.
one-to-one: two different x go to two different y.
On a graph this means that any horizontal line intersects the graph only zero or one times, not more.
Try to show this is false for your example: Try to find a y which two different x map to:
Let the two values of x be a and b
then a/(2a+1) = b/(2b+1)
2ab+a = 2ab+b
a=b
so if two values of x map to the same y, then they are the same,...
Answer to:
Q1 :- A process is out of control if 4/5 observations on the same side of the mean are at least one standard deviation from the mean. Calculate the probability that 4/5 observations from a bell-shaped curve are at least 1 standard deviation from the mean.
You can only calculate this numerically or using tables.
In a normal distribution 68.27% of the measurements lie within one standard deviation of the mean.
The probability that one measurement lies outside this is p=0.3173
Now use the binomial distribution with n=5, i=4, p=0.3173 to calculate the answer.
Answer to:
Can someone teach me a general method of converting base numbers? (I.E. Binary to Hexadecimal, OR Base 14 to base 20)
Easiest is probably to convert to decimal and then to the new base.
Converting to decimal:
If the number was 1234 in base b
then thus means 1*b^3 + 2*b^2 + 3*b + 4
do that sum, and you get the number in decimal.
To convert decimal to another base b, first write in decimal the numbers 1, b, b^2, b^3 etc until multiplying by b would exceed the number you are trying to convert.
Say you...
Answer to:
The amount of petrol purchased at a local service station per car has a normal distribution with a population mean of 45L with a population standard deviation of 5.3L. 99% of cars will purchase between 32.651L and 57.349L. %0
32.651L is 12.349L below the mean
12.349L/5.3L is 2.33 standard deviations below the mean
57.349L is 12.349L above the mean
also 2.33 standard deviations above the mean,
What is the area under the standard normal graph between -2.33 and +2.33?
Answer 99% - 1% = 98%
So FALSE: Only 98% of cars lie in that range.
To get 99% you would have to haveonly 0.5% missing at each side.
...
Answer to:
What is the probability of picking a red ball, if, from one red ball and six green balls (seven balls!), four balls are picked?
Number of ways of choosing four balls from seven is "7 choose 4" sometimes written 7C4 and is calculated as (7*6*5*4)/(4*3*2*1) = 35
To FAIL to pick a red ball, you have to choose 4 green balls.
Number of ways of doing that is 6C4 = (6*5*4*3)/(4*3*2*1) = 15
So there are 20 ways of choosing four balls containing at least one red.
Probability = 20/35 = 4/7 = about 57 %
Answer to:
My term grade worhts 60% and my examinations worths 40% it means that the term is worth more. So my question is if i get a 80% for my term grade and a 93% for my exam how can i calculate the grades to see what my overall will be like?
80% = 80 percent = 80 per cent = 80 per 100 = 80/100 = 4/5
Four fifths of your full term grade's worth is four fifths of 60%.
One fifth of 60% is 12%, four fifths are 48% - that's how much you get from the term grade.
Same idea: 93% of 40% is (93/100)*40 and thats how much you will get for the exam. Add them together.
But you may not get as much as 93% on the exam, because...
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Answer to:
I asked on line free legall advice about getting a refund And was told I was entitled but the company are at it refusing. I am in UK what legal jargon can I quote to make them poo it n see i mean business
Try going over their head.
If you can talk to a manager in person, that may help.
If the local company don't help you, write a short (paper) letter to their head office if there is one, tell them clearly what happened and why you think you're entitled to a refund and make sure you use the word "complaint" somewhere in your letter. It might still be worth doing this even...
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Answer to:
Are you having problems seeing answers on questions in ab?
yes, there seems to be a delay.
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Answer to:
Solve for x: 3/4 (x - 8) = 1/2 (2x + 4)
What bit of the question are you stuck on?
Think of the equation as a balance with two balance pans.
If you do the same to each side, the scales will stay balanced.
The aim is to turn one side into 'x' so the other side will have the answer.
See the fractions? Fractions make it harder. You can eliminate fractions by multiplying through by the common denominator....
Answer to:
The waste gas product of photosynthesis is an important reactant in what cellular process?
respiration (this is a fancy name for breathing).
The waste gas of photosynthesis, is oxygen. Which we breathe!
Answer to:
I was just playing around with some noise making software, and I was generating tones all over the place from 5 to 40,000 hertz. And now all of a sudden I have to go poop. Is it possible that I hit the "brown note"?
Well the brown note is just a myth, so it's not possible.
Since you obviously knew the brown note existed, it was probably psychosomatic: part of you expected it to happen, so your body made it so!
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Answer to:
What is combustion?
Combustion is the exothermic reaction of a substance burning in a gas. Usually the gas is air or oxygen but others are possible: iron will burn in chlorine.
exothermic means gives out heat.
The reaction is usually a combination of atoms/molecules to make larger ones.
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Answer to:
If I stacked quarters, how many quarters would I have to stack to reach the surface of the Moon?
It's not possible, but if we assume it is, then the Moon is about 384,403 km away
and a quarter is 1.75mm thick.
Division: 220,000,000,000 quarters would get you there.
Thats $55 billion.
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Answer to:
What is the value of the following expression: (x-a)(x-b)(x-c). . . (x-z), so that there are a total of 26 factors, with each letter of the alphabet subtracted from x in one of the factors?
(x-x) is zero. Therefore the whole thing is.
Answer to:
Name a number which is inbetween a square of a number and a cube of another number?
Let the square be 0. It's 0 squared.
now pick the cube to be any extremely large cube.
There's lots of numbers in between.
I don't think that's what you meant.
I think what you are asking is for three consecutive integers a^2, b, c^3, or c^3, b, a^2.
So c^3 = a^2 + 2
(or c^3 = a^2 - 2)
I have found two solutions:
0 is in between -1, the cube of -1 and 1...
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Answer to:
Find the probability that at least 2 tails will appear in flipping a coin four times
no tails: HHHH
one tail: HHHT HHTH HTHH THHH
two tails: HHTT HTHT THHT HTTH THTH TTHH
three tails: HTTT THTT TTHT TTTH
four tails: TTTT
At least two tails = (6+4+1)/(1+4+6+4+1) = 11/16
Answer to:
If 3 men and 3 women are randomly seated in a row, what is the probability that they will alternate man, woman, man etc.?
There are 6*5*4*3*2*1 ways to seat six people in a row.
There are two ways to get alternating men and women:
MWMWMW and WMWMWM
in each case there are 3*2*1 ways of seating the men and 3*2*1 ways of seating the women.
Total number of ways = 2*3*2*1*3*2*1
Therefore probability you seek is (2*3*2*1*3*2*1)/(6*5*4*3*2*1)
= (2*3*2*1)/(6*5*4) = 1/10
I can't instantly see that...
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Answer to:
What is a t test?
The t test is used to measure if the mean of a population is less than a given value, based on small samples of the population, and thus it can be used to work out the confidence limits for the mean of a population.
An example would be to find the confidence limits for the mean proportion of voters voting Democrat in the next election based on a poll of a sample of the population.
The...
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Answer to:
Hi. I need help. will you help me please?
Asking for points is against the rules.
Answer to:
N!= 1x2x3x4x5...n is there anything like that for addition? (ie 1+2+3+4+5...n=something n)
There is something similar, you can use the sigma notation to represent 1+2+...+n
There is an example here:
http://mathcentral.uregina.ca/QQ/database/QQ.09.07/h/jamelia1.html
But you don't need a special notation because the sum is easy to work out,
1+2+3+...+n = (n(n+1))/2
and the formula is simple. The factorial hasn't got a simple closed formula.
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Answer to:
Which is better, to be a human, and to die after about 100 years (if you are lucky), or to be a jellyfish, and to be immortal?
I prefer being human, but, you know, my friend Jack the jellyfish prefers to be a jellyfish. The idiot.
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Answer to:
Have you ever felt that you thought of something before someone else claims to have invented it?
I thought of something. A small usb device shaped like a little camera. You'd wear it like a necklace, or keep it as a keyring, and if you saw something you wanted to photograph, you could just press a button within seconds, without having to navigate through the menus of your phone or wait ages for your camera to turn on, causing you to miss whatever it was you wanted a picture of.
...
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Answer to:
Could a 4th Dimensional being (if they exist) see time?
If their fourth dimension is our time, then this is like asking "Can a 3rd dimensional being see height?"
I guess the answer is yes.
If none of their dimensions is our time, then no!
Answer to:
You combine 50 mL of small BBs with 50 mL of large BBs and get a total of 90 mL of BBs of mixed size. Explain.
Reminds me of a school experiment.
Teacher takes a glass and puts stones in it. He does this until no more stones can be added and says 'its full, right?'
He then takes some gravel and by shaking the glass can get some gravel between the stones and says 'its full, right?'
He then then takes some sand and shaking the glass again, can get some sand into the glass....
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Answer to:
Is there anyone trying to make faster than light space-travel possible? what field does one enter to help with this research?
You need physics, and you need to know quite a bit of it so you can recognise rubbish from potential ideas.
You'll need to know about dynamics and quantum mechanics and electromagnetism and relativity and possibly gravity, and a whole lot of math too.
There's a guy trying to make a time machine from very strong magnets, causing an interaction between light and gravity. Faster than...
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Answer to:
How can i break the laws of physics?
how can you break the laws of physics?
By finding a phenomenon so strange as to not be explained by the current laws of physics.
Of course, the current laws of physics are pretty good, ... you'll have to look REALLY hard to find this phenomenon.
Like building a circular tunnel 27km around and smashing bits of atoms together at a fraction of the speed of light, for example!
Answer to:
A woman holds a hand mirror one foot behind her head while standing 4 feet from a dresser mirror.. How far in back of the dresser mirror is the image of the flower in her hair? (the flower is on the backof her head)
If she were to turn round, she'd see the hand mirror one foot away, and then one foot beyond that would be the image of the flower.
So the flower image in the hand mirror is 2 feet behind her.
If she turns round again and looks at the dresser mirror, the mirror is 4 feet away, her image is another 4 feet away making 8 feet, and the flower image is two feet further making ten feet.
...
Answer to:
A liter of oxygen has of 1.4 g and the oxygen molecule has a mass of 32 amu. How many oxygen molecules are there in three liters of oxygen?
1 amu = 1.660538782×10^−24 g
Answer = 3*1.4/(32 * 1.660538782 x 10^-24)
or just put (3 liters * (1.4 g per liter)) / (32 amu)
into google
Answer to:
Given that 12 g of carbon combines completely with 16g of oxygen to form carbon monoxide, how much carbon monoxide (in grams) can be made from 24 g of carbon and 80 g of oxygen?
12 g carbon + 16 g oxygen = 28 g carbon monoxide
another 12 g carbon + 16 g oxygen = 28 g carbon monoxide. 56 g carbon monoxide produced so far.,
Warning: Stock low: out of carbon error. Please order more carbon.
Answer to:
What is the qualitative and quanlitative information given by the formula Ca3(PO4)2.
Qualitive: contains phosphate groups, and calcim ions.
phosphate group contains phoshorus and oxygen.
Quantitive: contains two phosphate groups and three calcium ions. Phosphate group contains one phosphorus atom and four oxygen atoms.
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Answer to:
Is the brain a gland?
No, a gland is a organ whose main purpose is to produce a fluid.
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Answer to:
If time travel to the past were possible, would it also be possible to make telephone calls to the past from the future? For example if I wanted to call myself in the past to warn myself not to do something I ended up regretting would that be possible?
If a person is able to travel back in time and return, then it seems likely that you can send a device which looks like a telephone, set to ring as soon as you enter the room, and deliver a prerecorded message.
As to two way messages, going from the assumption that human return trip time travel is possible, then you can send a device which receives infomation, perhaps for arguments sake in...
Answer to:
What observatory can be used to observe the buckling of the space itself?
The LIGO gravitational observatory is looking for the buckling caused by gravity waves.
If you belive Einstein, all you have to do is use your own eyes as evidence of the seasons and therefore the orbit of the Earth about the Sun: From a frame of reference centered in the Sun, Earth orbits in a curved path because space is bent by the Sun.
(Oddly, from the point of an Einsteinean frame...
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Answer to:
If you had an iron ball that weighed 1000 lbs. on earth, and one that weighed 100 lbs. on earth, how long would it take the the small ball to orbit the other large one out in space? Assume they are ten meters apart.
The formula is
period = 2*pi*sqrt(a^3 / (G (M1 + M2))
where a is the sum of the semi-major axes, which in your example, is 10 meters if we assume they orbit in circles.
I put 2 * pi * sqrt(((10 meters)^3) / (G * ((100 lbs) + (1000 lbs))))
into google and it said 12.6 days.
Answer to:
Which likely has more mass, the air that we inhale or the same volume of air we exhale?
Every molecule of O2 that the body absorbs in the lungs(mass: 32g/mol) is converted to one molecule of CO2 (mass: 44g/mol) which is exhaled.
So it would be greater even if you didn't allow for water vapour as well.
Answer to:
What is the resistance of a 2.5m length of copper wire 1.5mm in diameter? How do I figure this out? Thanks
The conductivity of copper is about 60MS/m
S is the unit of conductance: Siemens and is 1/ohm.
This means a cube of copper of side 1m has a resistance of 1/60MS = 16.7 nano ohms
Stretch this out to 2.5 m long and it will have 2.5 times the resistance (more stuff to tunnel through).
So that's 41.7 nano ohms.
Squash the block so its only 1mm high and it will have 1000 times the...
Answer to:
What is the resistance and current through a 60W light bulb if it is connected to its proper source voltage of 120V? Repeat for a 100W bulb. How would I figure this out? Thanks
Here are the useful formulae you need to remember:
V = I R
Power = V I
Eliminating V or I from these gives you:
Power = I^2 R
Power = V^2 / R
In your question you need R given Power and V.
The fourth equation can be rearranged to give:
R = V^2/Power.
R = 120^2/60 = 120*2 = 240 Ohms
You also need I given Power and V.
The second equation can be rearranged to give you:
I =...
Answer to:
What is the resistance and current through a 60W light bulb if it is connected to its proper source voltage of 120V? Repeat for a 100W bulb. How would I figure this out? Thanks
Here are the useful formulae you need to remember:
Power = V I
V = I R
You can use these equations to eliminate V or I to give these equations:
Power = I^2 R
Power = V^2 / R
You have : Power and Voltage.
You want: resistance. The third equation has just power, voltage and resistance, and you can rearrange it to give you
resistance = Voltage^2/Power
You have: Power and...
Answer to:
Suppose that you have a 500 ohm, a 900 ohm, and a 1.40k ohm resistor. What is A. the maximum and B. the minimum resistance you can obtain by combining these? How do I figure this out? Thanks
If you put the resistors in series, then the formula is:
Rseries = R1 + R2 + R3
So, doing everything in kohm:
0.5+0.9+1.4 = 2.8kohm in series.
If you put them in parallel, the formula is:
(1/Rparallel) = (1/R1) + (1/R2) + (1/R3)
In this formula you are really adding conductances instead of resistances. Conductance = 1/Resistance and is measured in siemens.
(1/0.5) + (1/0.9) +...
Answer to:
Solve for x 2x-1
For the uninitiated, if you asked to solve a formula for a value of x, it means find the value of x which makes the formula equal *zero*.
Answer to:
If 24% of all students went away for spring break, what is the probability that 3 students went away?
The probability that 3 students picked at random went away does depends on how many students there are altogether.
But if there are a large number of students then the answer is approximately:
(0.24*0.24*0.24) = 0.0138
Answer to:
One night a certain motel rented 3/4 of its rooms, including 2/3 of its air-conditioned rooms. If 3/5 of its rooms were air-conditioned, what percent of the rooms that were not rented were air conditioned? a) 20% b) 33.3% c)35% d) 40% e) 80%
Suppose the motel has 60 rooms.
It rents out 45 rooms.
15 were not rented.
It has 36 air conditioned rooms.
And two thirds of 36 is 24.
24 of the air conditioned rooms were rented.
12 of the air conditioned rooms were not rented.
Proportion of not rented rooms that were air conditioned = 12/15
= 4/5 = 80%
Answer to:
Can a proportion be rewritten by using the means as extremes and the extremes as means?
Odd terminology.
I assume you're asking if a:b::c:d implies b:a::d:c
Yes it does.
Answer to:
Sally scores 1.5 on this test. How many standard deviations is Sally from the mean?
Here's how you do these:
find the mean (m)
find the standard deviation (s)
Answer: (1.5-m)/s
Answer to:
Give an example which will be symmatric as well as antisymmetric......
Equality is also symmetric as well as antisymmetric.
Symmetric: aRb implies bRa.
This is true for equality: a=b implies b=a
AntiSymmetric: aRb and bRa together imply a=b
Well a=b and b=a aren't even both needed to show a=b
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Answer to:
Give an example with justification , of a relation which is symmatric as well as anti symmatric.
A symmetric relation is one where aRb implies bRa.
equality is a symmetric relation.
By definition, but also because if a=b then b=a!
An antisymmetric relation is one where aRb and bRa together means that a=b
An example is "<=" (less than or equal)
if a <= b and b <= a then a=b
Answer to:
Phillips can eat 32 lollies inan hour. his brother can eat the same amount in 3 hours how long will it take both of them together to eat 32 lollies
In three hours they can eat 32*3 + 32 = 128 lollies
32 lollies is one quarter of 128 lollies
so it will take then one quarter of three hours.
or (3/4) hour
or 45 minutes
Answer to:
On Saturday you take 200 mg of a drug, by Monday, 120 mg remain in your body. What is the daily continuous decay rate for the drug in our body?
I guess we're assuming that the rate you lose the drug is proportional to the amount that is there. This is probably a large oversimplification.
The equation is
drug = 200 e^(- a t)
for some constant a
You know that 200 e^(- a (2 days)) = 120
- 2 a = ln(120/200) = -0.51
a = 0.255
at a time t, the instantaneous rate is -200 a e^(- a t)
= -51 / 1.29^t (mg per day)
Answer to:
Given the latitude and longitude of two points on the Earth, how do you calculate the (great circle) distance between them?
Great circle distance on a sphere is:
Distance = R arccos(sin(lat1)sin(lat2) + cos(lat1)cos(lat2)cos(difference in longitudes))
arccos is also known as the inverse cosine, inv cos or cos^-1
R represents the radius of the sphere
Earth's radius is 6370 km
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Answer to:
Find the linear approximation of 13.2^2
*the* linear approximation?
(1 + x)^2 is approximately the linear sum 1 + 2x for small x.
It wouldn't be a good idea to try this for: (1+ 12.2)^2
I can make x smaller by dividing:
13.2 is 1.1 * 12
so (13.2)^2 = 12^2 * (1.1)^2
now I can use the linear approximation with x=0.1 to get
(13.2)^2 = 144 * 1.2 = 172.8
In this case, it would have been easier to do
13.2^2 = 1.1^2...
Answer to:
Building an octagon deck, with all sides equal in measurement. The perimeter is 128ft, the distance from center of the deck to any side is 19ft, each gallon of sealant covers 125ft. what is the area of the deck? How many gallons of sealant take to seal it
128/8 makes 16ft sides.
The diameter is 16 + 16 sqrt(2) = 38.6 feet
The whole shape fits in a square which is 38.6 by 38.6 = 1492 square feet.
The four missing corners can be put together with their corners inwards to make a square with 16ft sides = 256 square feet missing at the corners from the large square.
Subtract the two makes 1236 square feet.
So you'll need nearly a whole...
Answer to:
Http://tinypic.com/view.php?pic=j7564g&s=3 The slope of the line is 2/5. The slanted line is perpendicular to the long line, the blue line is 8 feet, and the other short (blue) leg is 1 foot. Please find the length of the slanted line and explain.
The slope of the long line is 2/5.
That means that 8 feet along the base it must have risen to 8*(2/5) feet = 16/5 feet.
That tells you the length of the vertical green line is 11/5 feet after you subtract the small blue line.
The trick is that the green triangle is "similar" to the big 14ft wide triangle under the long line.
They both have a right angle and the narrow angle is...
Answer to:
How do you length of a base edge for a square based pyramid when given the volume?
If you make a pyramid like solid by joining all points on the base to the apex, then the volume is one third of the area of the base times the perpendicular height. This is true whatever the shape of the base.
So base area = volume/height
and if the base is a square, then the base edge is sqrt(volume/height)
You didn't tell us the height, so I can only assume that the diagonal slant...
Answer to:
Can someone explain the origin and purpose of e [~2.718...], the base of 'natural' logarithms? Why is it 'natural'? Why not base 2 or 3 instead of this irrational number? What is its proper name? Thanks.
e was invented by Leonard Euler, and is sometimes called Euler's constant, but it's proper name is still 'e'. Euler is pronounce "Oiler".
I asked the teacher this question at school, and he gave a vague answer, but now I think I have a better one.
Take the formula a^x, where a is some number. Say 2^x.
2^0 is 1
2^1 is 2
2^2 is 4
2^3 is 8
and so on.
You...
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Answer to:
Which is closer to infinity: A googol or zero?
How would you measure it?
Say you have to walk to infinity. Even if you had already made a googol steps, you still have an infinite number of steps to go, the exact same amount you had to start with. So in that sense, infinity is exactly as far from a googol as it is from zero.
On the other hand, you can prove that a googol is closer in the sense that you don't have to walk those...
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Answer to:
What is the mass of a person who is 6 foot tall and weighs 250 pounds?
The answer is (250 g_e/g_p) pounds mass.
Where g_e is the gravitational acceleration of Earth.
and g_p is the gravitational acceleration of the planet where he was weighed...
Answer to:
Is there a graphing calculator that can graph circles?
The original graphing calculator, was a pair of compasses and a straight edge. Was good enough for Euclid. Even Newton did his math the same way, before algebra was invented.
http://en.wikipedia.org/wiki/Compass_%28drafting%29
EDIT: Note to self: AB really doesn't like links with parentheses in!
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Answer to:
Why isn't one a prime number?
1 used to be considered a prime.
Now it is considered to be a "unit".
The reason that it was demoted is the Fundamental Theorem of Arithmetic.
This states that every number greater than one is the product of one or more primes AND if you put the primes in order, this "prime fingerprint" is the only possible product.
For instance 60 = 2*2*3*5
no other product of...
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Answer to:
I am building a retaining wall. It's a quasi-semi-circle. It's diameter is 7 ft. Part of the radius is 4 ft. The other part is 3 ft. The arc goes out 3 ft. How do I figure out the measurements for the outside perimiter?
I'm not certain what shape you are describing.
Take the 7ft diameter, you say the radius is 4ft on one side. So the "center" is 4ft along this diameter.
If you put a peg there and start drawing this shape with a piece of string from the other end, the string starts at 3ft, but you imply the shape doesn't go more than 3ft away from diameter. So the most logical shape is...
Answer to:
Solve equation: Give solutions in radians: 2sin^2x-7sinx+3=0.
Let (capital) X = sin x
then your equation is 2 X^2 - 7 X + 3 = 0
which is a simple quadratic, with two solutions for X which is sin x
You're now looking for the angles which correspond to that sine.
One of the values of X has no corresponding angle.
For the other value of X you get a ratio for the angle which corresponds one of the standard angles:
The angles in a right triangle...
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Answer to:
Find the exact values of Sin, Cos, Tan of given angle, -105.
I haven't been able to figure this one out.
Hints:
sine and cosine are like waves.
They repeat every 360 degrees.
Sine starts at 0 goes up to 1 at 90, back down to 0 at 180.
The portion from 180-360 is the negative of the portion from 0-180. It goes under the x-axis instead of over [ sin(x+180) = -sin(x) ]
Sketch this on your paper.
Cosine is similar, but it starts off at 1
cos (x) = sin(x+90)
Sketch this one in a different...
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Answer to:
If I have a shape with a different length on each of four sides, how do I find the area? My geometry is a little rusty. Is it possible to average the opposing sides before multiplying them?
If you have the coordinates of the points (x,y)
then for each point, add: thisx*nexty - thisy*nextx
so:
+ x1*y2 - y1*x2
+ x2*y3 - y2*x3
+ x3*y4 - y3*x4
+ x4*y1 - y4*x1
And then divide by two.
Answer to:
Do you consider links (to other AB answers, to external pages, etc. - NOT Spam) as answers to questions? Example, if the answer is "See <link>", and it's to an AB answer page where it DOES answer the question, is it an answer or "just a link"?
AB rules say the answer should not *just* be a link to another site. The internet is not static, if the link dies the answer is uselss.
But, I occasionally put in a link to an AB answer: what happens is that the question is really a duplicate. I mark the question as duplicate and give the person who asked it a link because it takes a long time for the moderators to deal with duplicate...
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Answer to:
A person has worked 36.5 years and managed to save $700,000. At the same rate, how much longer would it take to save another $300,000?
Well if this person puts the money under the mattress, and keeps the same salary the whole time it will take (3/7)*36.5 years = approx 15 years 8 months
Pay rises and interest from savings will reduce this figure.
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Answer to:
I'm stuck on how to differentiate:
(3x+2)
--------- * (x^-5+1)
x
Any help would be appreciated!
Differentiation is a mechanical process.
If DA represents the derivative of a formula A with respect to x then
D(UV) = U DV + V DU
D(U/V) = (U DV - V DU) / V^2
D(U+V) = DU + DV
Dx = 1
Dk = 0 where k is any formula without an x
D(U^n) = n U^(n-1) DU where n is an integer
D(log U) = (DU)/U
That's more rules than you need for this question.
Your first step might be to put U =...
Answer to:
How can one solve the equation 0=(8x^3) - (15x^2) + 1 for x?
The answers I get are strange, they're not simplifying into some sort of fraction or radical like I would expect. I'm pretty close but it's just not working out right. Any ideas?
Have a look at
http://en.wikipedia.org/wiki/Cubic_function
There are several methods there for working out the answer.
The general form of the answer is
cbrt(c1+sqrt(c2))+cbrt(c1-sqrt(c2))
so it's not some simple radical
It's hard to solve a cubic exactly. I did manage it once as part of another answer.
See http://www.answerbag.com/q_view/148127
for all the blood and gore.
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Answer to:
If i have an equation for displacement e.g. s=3t^2 - 2t^3, in order to find maximum and minimum values, do i differentiate twice and find where that equation equals zero? so 6-12t = 0, t=0.5 If so, how do i then find the maximum, and minimum acceleration?
displacement = 3t^2 - 2t^4
velocity = 6 t - 4 t^2
acceleration = 6- 12 t
acceleration is linear and decreasing in t, which means its maximum and minimum will be at the start and end of the time interval.
If the time interval is t=[0,1] then the max and min acceleration are 6 and -6
The answer depends on what the time interval is that you want to find the minimum and maximum values over.
Answer to:
_ _ _ + _ _ _ = _ _ _ Use digits 1,2,3,4,5,6,7,8,9 to fill the nine blanks. each digit may be used once only There are 320 ways of doing it can anybody give me as much as you can?
Label the nine blanks:
ABC + DEF = GHI
Swapping A and D doesn't affect the answer, neither does B and E or C and F.
So only have to consider combinations where A<D, B<E, C<F and then multiply by eight for those swaps.
I have tentatively come to the conclusion that you can't split 1-9 into three single digit sums, so there must be a carry from the units to the tens or...
Answer to:
Find a forumla for this data(note the second number is not exact) 1=110.5, 5=15695, 25=1528960, 100=125664453
and the other three are exact? What an odd question.
You can fit a quadratic through the other three points to give:
f(x) = ((x-25)(x-100)110.5/((1-25)(1-100))) + ((x-1)(x-100)1528960/((25-1)(25-100))) + (((x-1)(x-25)125664453)/((100-1)(100-25))))
roughly though:
10^0 -> 10^2
10^(1.4) -> 10^6
10^2 -> 10^8
which makes the formula aproximately 110.5 * x^3
The first number...
Answer to:
How can you make the numbers 123456789 add up to 100 while still leaving them in that same order?
http://www.answerbag.com/q_view/162844
Answer to:
Let C be the matrix C=1,2 2,2 a.find the determinant of c b.find C to the power of -1 c. calculate C to the power of 2 = C xC d. calculate (C -1)square and (Csq)-1 and check they r the same
a b
c d
determinant = ad - bc
inverse (C^-1)
is
d -b
-c a
divided by the determinant
square is
aa+bc ab+bd
ac+cd bc+dd
How did I find that:
To multiply: If you want say, element with row2,col3 in A*B
You take the 2nd row of the first matrix A, and the 3rd column of the second matrix B, and you imagine twisting the column 90degrees to the left and placing it on top of...
Answer to:
How do you find the circunfrence of a baseball bat then calculate the wait its so hard
Approximating the bat by a cylinder:
The circumference is pi times the diameter.
The volume is one quarter the circumference times the diameter times the length.
The weight is the volume times the density.
Answer to:
If f(x) = any function g(x)= any function & then we have to find Composite Functions either fog or gof. but My question is that if we have given fog= something and gof = something how do we separate them in original functions i-e f and g?
It's not always possible to do what you're asking.
If f(x) = 33x and g(x)=15x then f(g(x))=g(f(x)) = 495x
and there are a number of ways of factorizing that 495 which won't nessarily get you 33 or 15.
So it depends on the example you have.
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Answer to:
Will someone please help me solve 4m-2=-3/2 and 3m-9=-5/3? I'm having a really hard time.
I don't know about you, but those fractions make it look harder to me.
I tend to do this: multiply every term in the equation by a number to help get rid of fractions.
Sometimes it takes a couple of goes.
So:
4m-2=-3/2
The denominator of the fraction is 2.
Multiply every term by 2:
8m-4=-3
fraction gone!
increase both sides by 4, they'll still be equal:
8m = 1...
Answer to:
How do i figure out a fraction to a negative power?
(p/q)^-1 means 1/(p/q) which is (q/p)
Similarly:
(p/q)^-n = (q/p)^n = (q^n) / (p^n)
That should make it easy.
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Answer to:
What is the probability of rolling three six-sided dice and getting a sum of 8? What are the odds?
There are 6*6*6 = 216 possibilities for three different colored dice.
To make 8:
1+1+6 in three ways.
1+2+5 in six ways
1+3+4 in six ways
2+2+4 in three ways
2+3+3 in three ways.
= 21 ways
Probability = 21/216 = 7/72
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Answer to:
Spherical geometry: if my home is at the antipodes of New Zealand, when I am asked if I come from New Zealand, is it right to answer that I come from the opposite direction?
It depends where you are when you are asked.
If you're at home there is no opposite direction to New Zealand, since all directions lead that way.
If you're in New Zealand, then there is no direction to New Zealand, you're already there, so there is no opposite direction.
Otherwise if you are anywhere else, yes, you are always right.
This English answer exactly matches...
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Answer to:
A word for three dimensional shapes that has a 12 letters
These ones have twelve letters:
tetrahedrons
icosahedrons
Is that the sort of answer you want, or do you want a general term for three dimensional shapes?
Answer to:
If you have an equation such as x=2^n, how would you solve for n?
i.e. You have a value of x, but are trying to determine the number of times that integer can be divided by two...
Take logs.
If x = 2^n
then
log x = n log 2
n = (log x)/(log 2)
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Answer to:
Please could you tell me what is the term for a number that when multiplied by itself gives a prime number.
Thanks in advance
S
You might be thinking of a "surd" or a "radical" BUT
There is no term for "A number that when multiplied by itself gives a prime number", some surds or radicals might match that defintion but not all.
Answer to:
How many 5 digit numbers that are divisible by 3 can be formed using 0,1,2,3,4,5 no repetitions allowed
You can tell if a number is divisible by 3 if its digital root is divisible by three. That means you add up all the digits repeatedly until you are left with one digit.
0+1+2+3+4+5 = 15 would give a digital root of 1+5 = 6
This IS divisible by 3, so all 5 digit numbers from 12345 will be divisible by 3. There are 5*4*3*2*1 = 120 of those.
The only other set of digits that will be...
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Answer to:
The sellers of a home "net" $108,373. after paying: a 6% real estate commission, a 1/2% transfer tax, $7000. of the buyers closing costs, $625 in legal fees, $125. pest inspection, and $186,352 in mortgage p
You either know the sale price and want the cost price or the other way around.
Either way there isn't enough information there to answer the question.
The method is:
net= sales - costs.
So:
$108373 = sale price - (0.06 * sale price) - (0.005 * sale price) - $7000 - $625 - $125 - $186353 - cost price
This gives an equation which can be rearranged to find cost in terms of...
Answer to:
If y is an interger, which of the following is always an even interger? (A) y + 1 (B) 4y (C) 4y +1 (D) .772
Perhaps if you imagine various numbers for y this will be easier:
For instance take the integers 0 1 2 3 4 5
After A they become 1 2 3 4 5 6
After B they would become 0 4 8 12 16 20
After C they become 1 5 9 13 17 21
After D they become .772 .772 .772 .772 .772 .772
Is it true that in only one of those cases is the answer always an even integer?
The proof of the answer has to do...
Answer to:
What is the shape of the graph of 9x + 7y= -1000? How do you know?
It's a line. A line that slopes downwards with a slope of 9 of y for every 7 of x: slope = (9/7).
At x=4 the value of y is -148 so the line passes through the point (4,-148)
How do I know it's a line?
Well ax + by + c = 0
is one of the standard equations of a line, and your equation looks like that if you put the 1000 on the other side.
I also know its a line because...
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Answer to:
Is saying "rate is decreasing by 0.0095 in^3 /min" the same as saying "rate= -0.0095 in^3 /min"??
Please please tell me it's correct. Or else Ill flunk my final exams in Calculus.
And which one did you write?
Neither statement is 100% clear.
They seem to be saying different things:
To say a "rate is decreasing by xxx" is like saying "the speed is decreasing by 5 mph / min". Presumably the speed is positive, but it is reducing.
And the second phrase doesn't make clear what a negative rate means. in^3/min is a flow rate. Like in a...
Answer to:
A worker,on 52% of shifts,forgets to shut off his machine at night,increasing the probability of a defect produced in the morning, from 3% to 17%. What is the probability that theworker didnt shut off the machine if a defect is randomly found one morning?
This is Bayes theorem, but I can't rember that, so imagine that every possible event occured, with its expected probability:
Suppose the worker worked for 10000 days. (because 1%*1% will work)
On 52% of those he forgot to shut off the machine:
that's 5200 days
On 48% he remembered = 4800
Of the 5200 days , after 17% the machine failed in the morning = 884 days
Of the...
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Answer to:
A photograph of a child has a width 2 inches longer than its length. The picture was made bigger by increasing both its length and width by 2 inches, its area increases by 20 square inches. What are the dimensions of the original picture?
Facts:
1) OW = OL + 2
2) NewArea = OldArea + 20
3) OldArea = OW * OL
4) NewArea = NW * NL
5) NW = OW + 2
6) NL = OL + 2
With the exception of OL and NewArea, all the other facts can be substituted into fact #2 and fact #4 to give:
2) NewArea = (OL + 2) * OL + 20
4) NewArea = (OL + 4) * (OL + 2)
These are equal so:
(OL + 2) * OL + 20 = (OL + 4) * (OL + 2)
OL^2 + 2 OL + 20 = OL^2 +...
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Answer to:
What is the polethagorean theorem?
It's very similar to the pythagorean theorem, that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides, but is more to do with finding the height of poles.
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Answer to:
What is a consecutive prime number and what is the difference between a prime number and a consecutive prime number?
consecutive just means "following in succession".
For example, you could call 11, 13 and 17 "consecutive prime numbers" as 11, 13 and 17 are the first three prime numbers when you start at 11.
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Answer to:
X(x+7)=411
x^2 + 7x - 411 = 0
(x + 3.5)^2 - 12.25 - 411 = 0
(x + 3.5)^2 = 423.25
x + 3.5 = 20.573 or -20.573
x = 17.073 or -24.073
check:
x^2 = 291.487 / 579.509
7x = 119.511 / -168.511
-411 = -411 / -411
sum = -0.002 / -0.002
(close enough, as I only found x to 3 decimal places).
Answer to:
1-(a+b)/(a-b)
put both terms over (a-b)
1 is (a-b)/(a-b)
so [(a-b) - (a+b)] / (a-b)
= (- 2 b) / (a - b)
Answer to:
According to a recent study, 1 in every 9 women has been a victim of domestic abuse at some point in their lives. We randomly and independently sampled 25 women and asked whether they have been a victim. Find the probability that more than 2
The formula is
P(i women have been a victim of domestic abuse)
= nCi p^i q^(n-i)
p is 1/9
q is 1-p
n is 25
25C0 = 1, 25C1 = 25, 25C2 = (25*24)/(2*1)
To do "more than 2" you have to find
1 - (P(0)+ P(1)+P(2))
Answer to:
5% of female population will get pregnant as a teenager. Study says pregnancies occur independently. Suppose 16 women were randomly selected. Find probability that 15 will not get pregnant.
Formula is
P(i pregnant) = nCi p^i q^(n-i)
p is 0.05
q is 1-p
n is 16
16C0 is 1, 16C1 is 16
Now find
P(0 pregnant) + P(1 pregnant)
which is the probability that at least 15 will not be pregnant.
Answer to:
39% chance a stock investment will end up in a total loss of your investment. Yo decide to invest 4 independent risky. Find probability one of your 4 investments becomes a total loss.
one, or one or more?
one: 4C1 * 0.39^1 * (1-0.39)^3
4C1 is 4
one or more = 1 - (4C0 * 0.39^0 * (1-0.39)^4)
4C0 is 1
Answer to:
How do you add/subtract and multiply/divide with error? For example, (24.3±0.1)+(26.5±0.1) = 50.8 ±?
It does depend on how you define "error".
24.3 +/- 0.1 could mean any number between 24.2 and 24.4
If you define it like that, then you can find the answer using interval arithmetic:
If [a,b] is an interval with a<b
[24.2, 24.4] + [a, b] = [24.2+a, 24.4+b]
[24.2, 24.4] - [a, b] = [24.2-b, 24.4-a]
[24.2, 24.4] * [a, b] = [24.2*a, 24.4*b] provided a and b are positive.
...
Answer to:
Please solve this equation for me using the completing the sequare method. x(sequred)-8x-3=0.
Square (x-a) and you get (x^2 - 2a x + a^2)
You have -8 where I have -2a ... a=4
Square (x-4) and you get (x^2 - 8 x + 16)
I only need to subtract 19 from this to get the left hand side of your equation:
(x-4)^2 - 19 = 0
(x-4)^2 = 19
Square root both sides:
x-4 = plus or minus sqrt(19)
x = 4 plus or minus sqrt(19)
Answer to:
The gravitational force of attraction between two masses varies inversely as the square of the distance between the. If the force of attraction is 4 lbs. when the masses are 3 ft apart, what is the force of attraction when the masses are 6 f
you doubled the distance = two times
so the affect on the force is the inverse of the square of two times.
which is the inverse of four times.
which is the inverse of multiplying by four.
which is dividing by four.
which is quartering.
so if you double the distance, you quarter the force.
Answer to:
Integrate 3 problems? 1.)(5/ 4x +3) dx 2.) (4x/ sqrt x^2 - 4) dx 3.) (e^cosx) sinx dx
You need to put more brackets in when you write in text:
5/4x+3 could be (5/4x) + 3 or 5/(4x + 3)
I think you mean 4/(4x+3)
In the second one I assume 4x/sqrt(x^2 + 4)
To solve:
Use change of variable.
Change of variable uses one of these rules:
Integral f(x) dx = Integral g(u) (dx/du) du
Integral f(x) (du/dx) dx = Integral g(u) du
where g(u) is the formula f(x) as it...
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Answer to:
How many combinations are possible if you had to pick 3 of 18 different numbers? Order does not matter, but none of the 3 numbers could be one more or less than another.
Not quite enough info.
What are the 18 different numbers?
Suppose they are 1 to 18.
There are 18C3 way of picking three of them, which is (18*17*16)/(3*2*1) = 816
Now I list the cases where we have adjacent numbers:
There are 16 cases where all three numbers are adjacent: 1-2-3 up to 16-17-18
The other possibilities are:
two adjacent + one other not adjacent:
1-2 plus one of the...
Answer to:
A Boeing 747 weighing 700,000 lbs is climbing at 15,000 ft, flying at about 200 mph, when a spark ignites the central fuel tank, causing the plane to break apart mid-air. About how many seconds does it take for the pieces of the fuselage to fall to earth?
You describe the TWA 800 accident.
The following plane reported "we saw an explosion out here[...]about 16,000 feet (4,900 m) or something like that, it just went down into the water."
This sentence was began 38 seconds after the explosion.
The NTSB data shows that the main debris probably took 30-40 seconds to hit the water.
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Answer to:
Help no one has answered this question
integration and evaluate problem? int [ -2, 6 ] (x^2)(cube root of (x+2)) explain how u do it please
cbrt(x+2) is really awkward when you've got x in there as well.
so use change of variable v=x+2
Now the problem becomes:
integral [0,8] (v-2)^2 cbrt(v) dv
Multiply out:
integral [0,8] v^2 cbrt(v) - 4 v cbrt(v)+ 4 cbrt(v) dv
But wait cbrt(v) is v^(1/3) ...
integral [0,8] v^(7/3) - 4 v^(4/3)+ 4 v^(1/3) dv
Each of the three terms can be integrated using the standard rule...
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Answer to:
How do you mutiply 67x4?
The easiest way is like this:
67 x 4
= (60 + 7) x 4
= 60x4 + 7x4
To do 7x4 you can use your tables to make 28
60x4 = 6x10x4 = 6x4x10 = 24x10 = 240 with tables.
Or you can use the rule that "x4" means double twice.
So 7x4 = 7 doubled twice = 14 doubled = 28
You can do that with the original number:
67x4 = 67 doubled twice = 134 doubled = 268
Or you can use the...
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Answer to:
From a standard deck of 52 cards, you are dealt 6 cards. What is the probability that you are dealt a straight flush? A straight flush is 5 cards in a row from the same suit. Aces can be high or low. Please show all work.
Ways of picking a straight flush:
Highest card can be A K Q J 10 9 8 7 6 5 = 10 choices.
Suit can be C D H S = 4 choices.
So there are 40 different straight flushes according to your definition.
The remaining card could be any one of the remaining 47 cards. So that would be 40*47 six card hands containing a flush.
But if you look closely, I counted some hands twice:
straight(3,4,5,6,7)...
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Answer to:
How dose this work when you take 3 numbers other than 0 ,starting with the highest to the lowest . Like 742 then reverse them 247 & subtract from the first No: = 495. Now take 495 & reverse it to 594 & add them & it always = 1089?
My digits are a,b, and c with a>b>c
abc = 100a +10b +c
reverse them:
cba = 100c + 10b + a
subtract:
100(a-c) + (c-a)
= 99(a-c)
= 90(a-c) + 9(a-c)
Rule for multiplcation of a digit d>1 by 9:
... 9(d) = 10(d-1) + (10-d)
So
If a-c is greater than 1, I now have
100(a-c-1) + 10(10-a+c) + 10(a-c-1) + 10-a+c
= 100(a-c-1) + 90 + (10-a+c)
now reverse the number:
=...
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Answer to:
FIND THE NUMBER OF SQUARE TILES WHERE 85 SUCH TILES ARE ALTOGETHER ALONG THE TWO DIAGONALS OF A SQUARE WALL?
So there are 85 tiles liying on one or the other diagonal?
That's an odd number for two diagonals, so the diagonals must intersect at a single tile in the center shared by both diagonals.
If you count that tile twice, then there are 86/2 = 43 tiles in each diagonal.
Since these are square tiles on a square wall, the entire wall must be 43 by 43 tiles
43 * 43 = 1609 + 240 = 1849
Answer to:
Please, find the sum of this equation. Please show all work.
30
∑ 10(1.05)^i+1
i=1
Your question is incomplete.
Is it find sum of (10*(1.05)^i) + 1 for i =1 to N?
= 10*(sum of (1.05)^i, for i=1 to N) + (sum of 1, for i=1 to N)
= 10*( (1.05^(N+1) - 1)/(1.05 - 1) - 1) + N
= 210*1.05^N + N - 210
check, when N = 1 we should get 11.5
210*1.05 + 1 - 210 = 11.5
when N= 2 should get 11.5 + 12.025 = 23.525
210*1.05^2 + 2 - 210 = 23.525
Answer to:
Cos 2x= 1/8. Can someone give me a step by step explanation on how they got this? I need to find this to the nearest hundredth of a radian. (*0=and <x<2pi)
when you have
x + 4 = 3
you have to subtract 4 from both sides to "cancel"
the +4 operation which is messing up the nice x on the left
when you have
cos y = (1/8)
you have to "cancel" out the cos operation on the left.
The opposite of cos is "arccos" same as "invcos" same as "cos^-1"
(but note: cos^-1 is quick and dirty...
Answer to:
How do you answer this? 586*56%?
56% is 56 per cent = 56 per hundred = 56/100
586*56/100 = 328.16
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Answer to:
Find all complex zeros of this Polynomial function. Give exact values. List multiple zeros as necessary. f(x)=3x^3 - 9x^2 - 31x + 5
Go here:
http://www.1728.com/cubic.htm
and find the answer.
Or. I saw in another answer that all the rational solutions are all of the form p/q where p is a factor of 5, the last number and q is a factor of 3, the first number.
That leaves few possibilities for p/q:
1,1/3,5/3,5 or -1,-1/3,-5/3,-5
x=+5 works: 3*125-9*25-31*5+5 = 0, so (x-5) is a factor.
dividing this out:
3x^2 *...
Answer to:
Cos-1(sin(pi/6))
cos^-1(sin(x))
How to do this for ALL values of x:
x is an angle in a right triangle.
We are given the sin of x = "opposite/hypotenuse"
But if we look at the other angle, y, then for that angle, the same ratio is the "adjacent/hypotenuse" which is the cosine.
So the sine of one of the angles in a right triangle, is the cosine of the other angle, and vice...
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Answer to:
A woman rides a bicycle for 1 hour and travels 21 kilometers. Find the angular velocity of the wheel if the radius is 35 centimeters. (Round your answer to the nearest hundredth.) The answer should be in rad/sec.
If the radius is 0.35m, the circumference is 0.7 pi metres.
21000/0.7pi = 30000/pi revolutions of the wheel.
Each revolution is 2pi radians so that's 60000 radians
60000 radians in 1 hour
= 1000 radians in a minute.
= 16.67 radians in a second.
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Answer to:
Probablity distribution of rolling a pair of dice a 100 times
The number of times you throw it doesn't make a difference to the probability of each throw.
On each throw there are thirty six possibilities for two dice, one red, one green.
Each possibility has a probability of 1/36
(red dice, green dice) =
(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)
(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)
(3,1) (3,2) (3,3) (3,4) (3,5) (3,6)
(4,1) (4,2) (4,3) (4,4) (4,5)...
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Answer to:
A vending machine will only accept quarters weighing between 5.48 and 5.82 g. What percentage of quarters will be accepted? How do i do this? The correct answer is .9806 but i dont know how to get that answer.
You need to know the average weight of a quarter, and the standard deviation of the weight.
Now you can compute what 5.48g and 5.82g are in "standard deviations above the mean"
Suppose the average weight of a quarter is 5.67g
and the standard deviation is 0.07g
5.48 is 0.19g below the mean = 0.19/0.07 = -2.714 standard deviations below the mean
5.82 is 0.15g above the mean...
Answer to:
Helllpppp! I don't understand counting techniques!
"A suitcase has a three digit combination lock, where digits in each position range from 0-9.
If the lock combination has 3 different digits, how many arrangements are there?"
If there are three different digits, the set of three digits is chosen from the set of ten digits 0-9.
There are "10 choose 3" or "10C3" ways of choosing 3 digits from 10
10C3 is (10*9*8)/(3*2*1) = 120
Now you have 3 different digits, there are 3*2*1 ways of arranging them.
Multiply those two numbers and get 10*9*8 = 720 as the number of ways of picking 3...
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Answer to:
I got a math problem I need to solve. I cant see the pattern. Its a number sequence where i need to come up with the next (2) numbers in the pattern. The numbers are as follows:
2, 4, 12, 14, 607, ?,?
The next number is 609
but the one after that is awkward:
12 was the first two numbers divided by two: 24 -> 12
607 = 1214 divided by two
so the next number = 607609 divided by two = 303804.5
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Answer to:
Vanderwaals radius WHAT IS Vanderwaals radius
It's Van-der-Waals radius, and it is the effective radius of the electrical field of an atom.
http://en.wikipedia.org/wiki/Van_der_Waals_radius
Answer to:
A line of equally spaced 20-foot light poles are to be part of a one-point perspective drawing. If in the drawing the first pole is 4 inches high, 10 inches from the vanishing point, and the second pole is 3.5 inches how far is the 2nd pole from the 1st?
The height and distances of the poles are in proportion.
So height/distance is the same for each pole.
For the first pole 4/10 = 0.4
For the second pole 3.5/x = 0.4
35 = 4x
8.75 = x
Answer to:
If a postcard 6" on the shorter side is in the shape of a Golden Rectangle, what is the length of the longer side?
6" times the golden ratio which is (sqrt(5)+1)/2
so (3sqrt(5) + 3)"
Answer to:
A conical rain gauge with radius 90mm and depth 180mm is filled with water at a constant rate of 150000mm3/s. At what rate is the depth of the water increasing when the depth is 100mm? (Note: volume of a cone is 1/3(pi)h(r2))
radius and depth are proportional.
So r is always h/2 and V = (1/3) pi h^3/4
dV/dh = pi h^2/4
so dh/dV is 4/ (pi h^2)
at a depth of 100mm, the depth changes at a rate of:
4/(10000 pi) mm per mm^3
Depth rate = 150000*(4/10000pi) = (60/pi) mm/s
Answer to:
26+64 divided by 10 x 23=
The problem with this question is that it is not clear what is "divided by".
"divided by" sometimes "grips tighter" as in
26 + (64 divided by 10) x 23
and sometimes it "grips loosely" as in
(26 + 64) divided by (10 x 23)
and sometimes it has the same "gripping power" as multiplied by, as in
26 + (64 divided by 10) x 23
...
Answer to:
Four points on a circle separate the circle into four congruent arcs: AB, BC, and DA. Is it true that AC is congruent to BD
Presumably you meant "AB, BC, CD and DA"
For arcs on a circle, congruent is the same as "equal"
Four equal arcs on an circle? They must all be quarter-circles.
AC must be a half-circle.
BD must be a half-circle.
AC is equal to BD
AC is congruent to BD.
Answer to:
Find the sum of a number + 105
Let n be the number.
Answer: n+105
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Answer to:
People say it is very UNLIKELY to be involved in a plane crash, but hasn't there been a lot lately?
Actually no, this year so far we have had 92 fatalities in airliner crashes, whereas at the average rate of fatalities we would have 140.
The average rate remains strangely constant: as techology gets better at reducing the chance that you will be involved in a plane crash, more people are flying.
A few years ago I calculated the chance of being involved in a fatal airliner crash is 2.2...
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Answer to:
If a 45-inch broom handle has a label centered at the Golden Ratio and near the upper end of the handle, how far is the center of the label from the upper end?
What does "centered at the Golden Ratio" actually mean?
The golden ratio is approximately 1.618
which is more than 1.
So longer than the length of the broom.
And the label is 27.81 inches away from the broom. Probably on the outside of the broom cupboard.
OR perhaps the question was supposed to be: The label divides the broom into two parts. The lower part divided by the upper...
Answer to:
One half percent of population has a particular disease. A test is developed for the disease. The test gives a false positive 3% of the time and a false negative 2% of the time. a) what is the probability that kate ( random person) tests positive?
Let's make 200 times 100 = 20000 kates representing every possibility for kate.
We know that 1/200th or 100 kates have the disease.
19900 kates do not have the disease.
Of the 100 kates that have the disease, 2 will get a false negative and 98 will be correctly diagosed.
Of the 19900 kates that do not have the disease, 3%, or 597 will get false positives. The remaining 19303 are...
Answer to:
Ok, can someone help me understand this? 'Cause I've come to the conclusion that circles cannot exist. If circles have infinite sides, then extending infinite lines from the center past the circle to a bigger circle will (more inside)
Circles are not really polygons with an infinite number of sides: there is a distinct difference, for instance, a circle has no corners and an infinite polygon has an infinite number of them.
Nevertheless in this instance the infinite polygon DOES work.
Take one "side" of your infinite polygon and draw the radials that I think you were talking about through center and each end...
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Answer to:
How do I solve 400*1.1^(n-1)>100n+300 step by step?
You can't get an exact closed form solution, but you can get an approximation.
divide by 100:
4 * 1.1^(n-1) > n + 3
Roughly sketch both sides.
The right side is a straight line, the left is an exponential. When n=1 the two sides are equal,
but when n=2 the inequality is false: 4.4 < 5 so the
left side is below the right on a graph, but because of the shape of the...
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Answer to:
What are the names of the different part of a decimal number (0.4)?
I know them as,
the whole number part (or the integer part),
the decimal point,
the fractional part (or the decimal part).
Answer to:
Two identical bags each contain 8 balls, four white and four black. One ball is drawn out of Bag 1 and another ball out of Bag 2 What are the chances that at least one of the balls will be black?
1/2 chance that first ball is white
1/2 chance that second ball is white
and since these are indpendent experiments, chance that both balls are white = (1/2)*(1/2) = 1/4
Chance that at least one will be black is the opposite of that = 3/4
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Answer to:
For what two fractions will the product always be between the two fractions?
Let the fractions be b and c with b<c
then b < bc < c
So 1<c
and b<1
If the fractions are positive, then they must lie either side of 1 for the product to be between them.
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Answer to:
What is the next two numbers 24, 33.6, 47.04, 6.856 What is the next 2 numbers .5, ,.6, 1.0, 1.9 3.5, 6.0
a) each number is (supposed to be) 1.4 times the last.
So
24 * 1.4 = 33.6
33.6 * 1.4 = 47.04
47.04 * 1.4 = 65.856
65.856 * 1.4 = 92.1984
b) each number is the last plus n^2/10
0.5 + 0.1,
0.6 + 0.4,
1.0 + 0.9,
1.9 + 1.6,
3.5 + 2.5,
6.0 + 3.6 = 9.6
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Answer to:
How do you find the volume of a cylinder using only spherical polar coordinates?
Let R be radius of cylinder.
Consider the part of the cylinder where a line through the origin passes through the walls of the cylinder.
That's all of the cylinder except two cones at the top and bottom.
maximum r for any elevation theta = R / cos theta
theta range is +/-arctan (h/2R)
Volume integral dV = r^2 cos theta dtheta dr dphi
Integrate succssively within the ranges dphi,...
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Answer to:
How many years would be in a olympaid?
olympiad = four years.
Answer to:
It costs $9 to buy 3 container of orange juice and 2 containers of milk. To buy 9 containers of orange juice and 6 containers of milk, it costs $27. What is the cost of one container of orange juice.
The second fact about orange juice and milk tells us no more than the first as it is just a multiple: the second person just bought three times as much stuff as the first.
So we really know is
3 orange juice + 2 milk = $9
and:
orange juice costs between $0 and $3
milk costs between $4.50 and $0
one orange juice costs
$3 minus two thirds of the price of milk!
Answer to:
What is the radius of a sphere centered at origin? with the most integer points on its surface. i mean the number of points (x,y,z) on surface with all 3 (x and y and z) are integers. the radius is any real number less than 25.
So you're looking for the most integer solutions to:
x^2 + y^2 + z^2 = r^2 with r<25
I checked this with a computer program
and the answer is r=21 with 270 points.
0^2+0^2+21^2 times 6 ways
4^2+5^2+20^2 times 48 ways
4^2+8^2+19^2 times 48 ways
4^2+13^2+16^2 times 48 ways
6^2+9^2+18^2 times 48 ways
7^2+14^2+14^2 times 24 ways.
8^2+11^2+16^2 times 48 ways.
EDIT:
I...
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Answer to:
Im making a target system for a 3d program and im trying to aim ahead of the other player i can get the angle to aim at for the point but i need to know where the point to aim at is the rest you need to know is on this pix reference
Nice question.
Other player moves as: (x0 + vx t, y0 + vy t, z0 + vz t)
Your position: (X, Y, Z)
Relative position of other player:
V(t) = (x0 - X + vx t, y0 - Y + vy t, z0 - Z + vz t)
Let D(t) be the magnitude of this vector, the distance to the other player at time t, theoretically calculated with Pythagoras.
Need to solve for D(t) = 18 t
because after t seconds your bullet...
Answer to:
If BD=Ce and BD bisects ABC and EC bisects ACB does it follow that ABC=ACB
I can't see a link or image provided with your question. Sometimes answerbag loses them.
From the question alone, does not follow.
Take any triangle ABC. Draw BD to bisect ABC of sufficient length such that D is not near the triangle.
Draw CE to bisect ACB and the same length as D.
Everything is satisfied, but ABC was arbitrary, not necessarily isoceles.
Answer to:
What is a even 3-digit number greater than 700 whose digits equal 11?
The first one is 704
The rest are:
722
740
812
830
902
920
Answer to:
How do I solve x+4 over x-5 is greater than or = to 1
(x+4) / (x-5) >= 1
It is tempting to multiply both sides by (x-5).
But you aren't allowed to.
You can only multiply inequalities by positive numbers,
or you can multiply by negative numbers if you change the sign of the inequality.
But we don't know if x-5 is positive or negative.
First method:
Split the possible solutions for x into the cases where x<5 x=5 and...
Answer to:
I often see entries in books and articles about the average life expectancy within a given cohort but is it equal to the average age of death?
Usually yes. Average age of death for people in that cohort.
Remember though that because some people die earlier than that age and are no longer counted, the average life expectency of those that survive continually rises.
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Answer to:
I am doing a science project and need 10 common items that would be considered a gas. Can you help me with this please?
Could be tricky.
Common items??
Air is a gas
it's a mixture of two gases:
Oxygen
and
Nitrogen.
Burn something wooden and you get Carbon Dioxide, which is a gas, and Water Vapour, which is a gas, and if the burning isn't very good you get poisonous Carbon Monoxide too.
Tap water is treated with Chlorine which is a gas, to kill off bacteria.
Go to a party supply...
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Answer to:
A plane flies with the wind traveling 2160 miles in 3 hours. When the plane flies in the opposite direction, against the wind, it takes 4 hours to fly the same distance. Find the rate of the plane in still air and the rate of the wind
When the plane flies with the wind, it's ground speed is equal to air speed plus wind speed.
Let V mean air speed, and W mean wind speed.
Average Speed = Total Distance / Total Time.
On the way,
V + W = 2160 / 3
When the plane flies against the wind, it's ground speed is equal to air speed minus wind speed.
On the way back:
V - W = 2160 / 4
You can find V or W...
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Answer to:
Two opposite vertices of a square are ( -1, 2) and ( 3, 2).What are the coordinates of the other two vertices? The answer is (1,0) and (1,4). Please mention the steps.
You wrote: "I want to know how I'll do it using either distance formula, section formula or area of a triangle formula"
Here's using ONLY the distance formula (this is not the easy way to do it, but you have a stupid teacher):
The distance between the two vertices is
sqrt( (x2-x1)^2 + (y2-y1)^2)
That tells you that the distance is sqrt(4^2 + 0) = 4
Half that...
Answer to:
Two similar polygons have perimiters of 48in and 40in. one side of the larger polygon has a length of 18in. find the length of the corresponding side of the smaller polygon. please help asap!!! due tomorrow and im stuck!!!!
You'll agree that the smaller perimeter
is 40/48ths of the larger one?
The same is true for any measured length on the polygons because this is what "similar" does.
Including a side length.
So the corresponding smaller side length is 40/48ths of 18 inches which is 18*40/48
Added extra fact: Any area on the smaller polygon is the square of (40/48) times the larger...
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Answer to:
I have study about the big bang theory and big rip theory does anyone know some info regarding this? I wanted to see if the info i know about it would kinda match.
The big bang is established theory - since the universe is expanding, if you wind back time, there must have been a point when all the matter was in the same place.
It started off very hot and very dense.
There follows a period of unbelievable expansion called 'inflation' where the universe is doubling in size many hundreds of times in a tiny fraction of a second, at some point...
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Answer to:
Is Na2O Sodium Chloride or Sodium Oxide?
These weird symbols like Na confuse matters, but most of them just stand for the English names of the elements themselves.
The O stands for Oxygen.
There's no Cl there for Chloride.
I think these are the only ones with weird symbols:
Na = Sodium (natrium)
Pb = Lead (plumbum)
Cu = Copper (cuprum)
K = Potassium (kalium)
Fe = Iron (ferrum)
Ag = Silver (argentum)
Au = Gold...
Answer to:
Do you think Hadron Collider will be a success or will be a fail?
Barring some sort of europe wide disaster, (and an econonic one looks plausible at the moment), it can't really fail:
If it finds the Higgs Boson, that's all well and good.
If it doesn't find the Higgs Boson, that's good too - maybe better: that's when all the theories go out the window and suddenly everyone is looking for what's really going on!
Answer to:
N2 + O2 --> 2 NO delta H = 43.2 kcal. Which is true: 1. 43.2 kcal consumed when 1 g of N2 reacts. 2. 43.2 kcal consumed when 1 g of O2 reacts. 3. 43.2 kcal consumed when 1 mol of O2 reacts. 4. 43.2 kcal consumed when 1 mol of NO is produced.
It takes heat to make 2NO, the reaction is endothermic, taking 43.2kcal per mol
It's per mol of each item in the equation, so its
42.kcal for:
1 mol of N2
1 mol of O2
making 1 mol of 2NO = 2 mol of NO
This should help you decide what the answer is.
Answer to:
If LIGHT isn't MATTER (the science term), HOW suck it get sucked into a BLACK HOLE
Light travels in the nearest possible thing to a straight line.
But a black hole bends time and space so much that the nearest thing to a straight line is a curved path leading into the black hole.
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Answer to:
What happens to the surface area as an object is scaled up or down?
If it's a uniform scale in all directions, then surface area increases as the square of the length scale.
Answer to:
How do you tell to use sin or cos?
Take a right triangle and mark one of the angles.
The longest side is called the hypotenuse.
The side opposite the angle is called the "opposite".
The side next to the angle is called the "adjacent".
The trig ratios are:
sin angle = opposite/hypotenuse
cos angle = adjacent/hypotenuse
tan angle = opposite/adjacent
And you can remember these using the mnemonic:...
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Answer to:
In the equation PV=nRT. What does R stand for?(serious answers please I don't have the time for jokes). THX
You have two answers saying what R means which I'm sure you already know since you know the ideal gas law, but you don't yet know what word it stands for.
Well I know the answer is here but I can't read it: http://jchemed.chem.wisc.edu/Journal/Issues/2003/jul/PlusSub/V80N07/p731.pdf
I have found that it was invented by Benoit-Pierre Emile Clapeyron in 1834.
I can't...
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Answer to:
Wy is pepsin not a peptide
A peptide is a short protein.
Pepsin is an enzyme that breaks proteins down into peptides.
Enzymes are typically huge proteins, and pepsin is no exception.
Answer to:
Are quarks and leptons actually fundamental, or are they made up of even more fundamental particles?
Noone knows, and we may never know.
However, Quantum Electrodynamics assumes the electron acts like a point source of charge, and it gives incredibly accurate results, so I believe the electron truely hasn't got internal parts.
The quark on the other hand is another matter.
Quantum Chromodynamics is very messy, and so inaccurate our best theoretical calculations can't even...
Answer to:
Why can't numbers be divided by zero?
division is the reverse process to multiplication.
A divided by B is defined as a solution to the equation for X:
B multipled by X = A
So in the expression: 2/0, X would be some number which would fit in place of X in the equation:
0 multiplied by X = 2
But there is no such number, so there is no solution to the division.
If it had been 0/0 you would get
0 multiplied by...
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Answer to:
My son and I are working together doing remodel construction work. We agreed to split the profits 1/3 for him and 2/3 for me. I can figure the split if we both work equal number of ManHour. How do you figure it if we work a different amount of ManHours
So, I figure you're paying your son a salary per hour, and you are getting twice that rate.
Suppose your son's salary is S dollars per hour, and yours is 2S dollars per hour.
If you work 5 hours you get 10S dollars.
If your son works 5 hours he gets 5S dollars.
So calculate how many lots of S dollars you have to pay out. That has to equal the amount of profit you made which...
Answer to:
Has anyone other than myself noticed that if you take the number pi and group the numbers in groups of 4 and multiply every number in that group together, each group can be divided by 3?
It's a nice idea.
The digits of pi are believed to be "normally distributed" which in this sense means that any combination of digits is as likely as any other.
Pick enough digits, and every possible combination of n digits will eventually appear. Including those whose products are not divisible by three.
Here are the first 100 digits of pi in groups of four:
...
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Answer to:
How do you prove that the number 0 exists?
Easy: It's right there in your question, between the word "number" and the word "exists"!
If the number doesn't exist, then your question doesn't exist either, and if you thought you saw my answer to it, you must have imagined it.
Answer to:
What is the limit as x approaches Infinity of (the sguare root of 7x^6-2x+591)/(-91x^3+207x-2006)
First divide top and bottom by x^3 to get
sqrt(7 - 2/x^5 + 591/x^6) / (-91 + 207/x^2 - 2006/x^3)
take out the 7 in the sqrt:
sqrt(7) sqrt(1 - 2/(7x^5) + 591/(7x^6)) / (-91 + 207/x^2 - 2006/x^3)
And the reason I did those two steps is:
sqrt(1 + eps) ~= 1 + (eps/2) for small eps.
So now I have an approximation, accurate for large x:
sqrt(7) (1 - 1/(7x^5) + 291/(14x^6)) / (-91...
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Answer to:
Use integration by parts to find the integral of x^2 cos 3x dx how do I solve this?
Integration by parts:
(u v )' = u ' v + u v '
Therefore:
Integral of (u' v) = u v - Integral of (u v ')
so if you have a product, you can integrate one term and differentiate the other, and you might have a simpler sum.
In your case u ' can be cos(3x) because that doesn't really get any more complicated if you integrate it.
And then v is x^2,...
Answer to:
Is gravity a form of energy that conforms to e=mc^2?
The answer is yes.
Lift a ball and it gains gravitational potential energy, and as a result of E=mc^2, it gains a little mass.
Thus in a sense, gravity itself gravitates.
Answer to:
I have a lever with a 25kg weight at one end and a pivot point just under the weight, how would i work out how much force is needed to lift that weight from the opposite end of the lever if the lever is 1m long?
If the pivot is truely under the center of gravity of the weight, it won't be lifted at all, just tilted from side to side.
The weight of the "weight" is given by F=mg = 25 kg * 9.8 N/kg = 245N
If the pivot is not quite under the center of gravity of the weight, but is D meters offset horizontally, then the weight causes a torque of force times perpendicular distance = 245...
Answer to:
Why is the ecliptic titled 23.5 degrees with respeoct to the celestial equator?
23.5 is really a suprisingly large amount.
The Earth's huge angular momentum is in a different direction to the rest of the solar system.
The sort of thing which can do this is a huge collision.
It is now generally accepted that during the Earth's early history as it was being formed, another planet formed 60degrees ahead of it in the orbit. Eventually the two Earth's...
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Answer to:
Because the gene for red-green color blindness is located on the X-chromosome, it is normally not possible for...?
... women to get it.
because normally a woman with a bad X gene will have only one X with the color-blindness problem, so the other X will make up for it.
Of course, they could inherit two bad Xs but that's much less likely.
Answer to:
How many kilocalories of heat does the operation of a 1299 W hair dryer produce each second?
If it were kilojoules, it would be 1.299kJ
But see google when you need to convert units too:
http://www.google.com/search?&q=1299+watt+*+1+second+in+kcal
I typed
1299 watt * 1 second in kcal
and google told me
0.310468451 kcal
which is 0.3105kcal to the accuracy given in the question.
Answer to:
Isn't that stuff about Sir Isaac Newton a lot of crap? Inventing gravity, I don't think so. Are you telling me nobody fell down or dropped a watermelon off a roof before he sat under an apple tree?
Galileo pretty much understood gravity as it exists here on Earth.
Isaac Newton's greatest contributions to gravity include proving that an inverse-square law of gravity would account for Kepler's Laws of planetary motion, thus proving that gravity is universal and not a merely Earthly phenomenon.
The math is pretty hard, even today using vector algebra instead of the geometry...
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Answer to:
The perimeter of a rectangular cornfield is 440 meters, the ratio of its length to its width is 7:4. what is the length and width of the field?
The ratio 7:4 means seven "parts" to four "parts"
Let one "part" be x.
Then
Length = 7x
Width = 4x
Perimeter = 7x+4x+7x+4x = 22x
22x = 440 meters
x = 20 meters
length = 7x = 140 meters
width = 4x = 80 meters.
Answer to:
A bag contains a number of red and green sweets, how many must i take to ensure i have 3 of the same colour
Always look for the scenario where you have picked as many as you can, but you still haven't got 3 of the same color.
So you must have two red and two green.
If you pick another, you're ok. So five is enough.
Answer to:
Is 4 a factor of 8?
Yes.
Hard part:
By defintion, for numbers 'p' and 'q', if there exists a number 'r' such that
pr = q
then p divides q and p is a factor of q.
In this case r=2
Easy part:
4 times 2 = 8
Therefore "4 divides 8" and 4 is a factor of 8.
Answer to:
How do u factor 3x - x cubed?
First: both terms have a factor of x.
Take that out:
x (3 - x^2)
The second term looks a bit like a difference of two squares. In fact it is (sqrt(3))^2 - x^2.
Any difference of squares a^2 - b^2 can be factored: (a-b)(a+b)
So the last step is :
x (sqrt(3) - x)(sqrt(3) + x)
Answer to:
Integrate sinx/x
Answer: Si(x) + C
Answer to:
I need the calculation for diluting 62.5mg in 5ml from 125mg in 5ml. the diutant is water.
Sounds like every 5ml has twice as much as you need.
So add another 5ml of water for each 5ml of solution and you'll have half the concentration.
Answer to:
5th term of (x+2)^9
(i+1)th term of (a + b)^n
is nCi a^i b^(n-i)
So plug in n=9, a=x, b=2, i=4 and crank the numbers.
Answer to:
4th term of (2x-y)^10
(i+1)th term of (a + b)^n
is nCi a^i b^(n-i)
So plug in n=10, a=2x, b=-y, i=3 and crank the numbers.
Answer to:
Is there a solution to the equation x=e^x?
xprofessor has answered this well for a real value of x, but is there any value of x which works?
There seem to be an infinite number of them, of which the first one I can find is near:
x = 0.318131507 + 1.3372357 i
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Answer to:
Wuts the difference between a acute angle and a chronic angle? i forget what the teacher sed.
I think your teacher was making a joke.
Illnesses can be acute or chronic.
A chronic illness is defined as any disease that develops slowly and lasts a long time.
An acute illness typically starts suddenly and is short lived.
Angles on the other hand can be:
acute - less than a right angle
right - 90 degrees.
obtuse - between 90 and 180
straight - exactly 180
reflex...
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Answer to:
I have 8 vertices what am i
You are a shape with eight vertices.
You might be an octogon.
But you might also be an octohedron.
Or a heptagonal pyramid.
Or many other shapes.
Answer to:
What's the pythagorean theorem?
In a right triangle, the square on the hypotenuse is equal to the sum of the squares on the other two sides.
In symbols:
a^2 + b^2 = c^2
This theorem has several thousand different proofs!
So it's probably true...
Answer to:
An aluminum block that is 1 m x 2 m x 3 m has a mass of 1.62 x 10^4 kilograms. What is the mass of the block expressed in grams?What is the ratio of mass (g) to volume (cm^3) for aluminum?
100cm x 200cm x 300cm = 6 000 000 cm^3
1.62 x 10^4 kg
= 16.2 x 10^3 kg
= 16.200 x 10^3 kg
= 16 200 kg
= 16 200 000 g
16 200 000 / 6 000 000
= 162 / 60
= 81/30
= 2.7 g/cm^3
which is cool, cause that matches the Density given on the page http://en.wikipedia.org/wiki/Aluminium
Answer to:
Find the center of the circle that you can circumscribe about triangleABC if a(0,0) b(3,0) c(3,2)
It will be on the bisector of the line ab
so it will be (1.5,y) for some y.
It will be on the bisector of the line bc
so it will be (x,1) for some x
It must be (1.5,1)
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Answer to:
Among many positive integers satisfying the equation(L.C.M of two numbers -H.C.F. of two numbers )=57.what is the pair satisfying the equation such that their sum is minimum.
Let the HCF be h and the two numbers ha and hb
then a and b are mutually prime, and the lcm is hab
We are told that:
hab - h = 57
So
h(ab - 1) = 57.
There are only two solutions to that:
h = 1 and ab=58
h = 57 and ab=2
This leads to these solutions:
h=1 a=1 b=58 the two numbers being ha=1 and hb=58
h=1 a=2 b=29 the two numbers being ha=2 and hb=29
h=57 a=1 b=2 the two...
Answer to:
What is 15 multiplied by 13?
15 multiplied by 13 is the same as 14 multipled by 14 minus one.
This happens whenever you have two numbers matching
x+1 and x-1:
(x+1) times (x-1) equals x^2 - 1
In general if the two numbers differ by an even amount you can do:
(x+n) times (x-n) is x^2 - n^2
Answer to:
If the coefficient of static friction between the tires and pavement is 0.75, calculate the minimum torque that must be applied to the 66cm diameter tire of a 1250kg vehicle in order to make the wheels spin.Each wheel supports and equal share of weight.
312.5 kg per wheel
F(weight) = mg
F = 3062.5 N
Sideways force = 0.75 * 3062.5 N = 2296.875 N
radius = 0.33m
torque = Force times perpendicular distance (radius)
= 2296.875 * 0.33
= 757.96875 N m
= 750 N m to the accuracy given in the question.
Answer to:
What Is The Correct Word For The Following Phrases...
A.Where A River Reaches The Sea
B.Where A River Flows Over A Cliff
C.Where A River Begins
DThe Area Of Land Which Supplies A River With Its Water
E.A Smaller River Which Joins A Larger One
A can be "mouth" or "delta" depending on the river.
B is surely "waterfall".
C is possibly "source" as in "the source of the Nile".
D, I don't know, but will guess "catchment basin".
E, "tributary"
P.S I looked up D, it says "watershed", I wouldn't have got that becasue that word is not used that...
Answer to:
Name the blood that carry blood to and from the lungs?
pulmonary arteries carry blood to the lungs and pulmonary veins carry the blood away.
Pulmonary means "of the lungs".
Answer to:
What is the theory named of sticking two flat pieces of metal together with oil so they still slide but will not pull apart
Possibly "capillary action".
http://en.wikipedia.org/wiki/Capillary_action
Usually used of water, but oil absorbs into a paper towel just as well as water.
Answer to:
Does a straight angle have to have a point on it, or can it be any straight line?
A straight line is an infinite set of points, so there are an infinite set of straight angles on it.
Answer to:
On a quiz show, you can pick two envelopes. One envelope has $1000 in it, one has $500, one has $300, one has $200, one has $50, and one is empty. How many different amounts can be won?
There are SIX envelopes to choose from.
If all the sums are different, then the answer is "6 choose 2" or 6C2 which is (6*5)/(2*1) = 15
So are they all different?
If you pick $50 the result will end $50 so will be different from all other sums without $50.
If you pick $1000, there's no other way to make that much, so will be different from all other results not choosing...
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Answer to:
Prove that in an A.P which consiits of od number of terms ,middle terms is equal to half of the sum of the first and the last term
if there are 2n+1 terms in the sum, then the middle term is the (n+1)th term.
Let 'a' stand for the first term, 'm' the middle and 'L ' the last.
from the first term 'a', each term increases by the constant difference d til the middle term m = a + nd.
from the middle term 'm', each term increases by the constant difference d til the end...
Answer to:
For what values of p is the series of sum ln k/ke power of p is convergence
Your question looks like:
sum over k of (ln k) /(k e^p)
But that is (1/e^p) sum over k of (ln k) /k
which doesn't converge as every term is greater than 1/k which means it is greater than the harmonic series which doesn't converge.
What else could you mean?
sum (ln k) / k^p which converges for p>1
I will give you a better answer if you add a comment to this answer...
Answer to:
(there is 23 hours and 56 minutes in one day but how many seconds
A solar day is 24 hours and is the average time it takes for the Sun to move about you and the earth and return to the same point in the sky.
There are 23 hours and 56 minutes in a sidereal day.
A sidereal day is how long it takes the stars to whirl about you and the earth instead of the Sun.
It takes the stars less time, because as we see it, the Sun is moving slowly the other way...
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Answer to:
H20 is water correct? Hydrogen and Oxygen are both ways of feeding a fire, or are in other words flammable. How come H20 as a compound does not ignite when the compound is made from 2 flammable elements?
Chemically combining something with oxygen is often called "burning", or "setting fire to it", or "pyromania".
Things that are completely burned do not burn any more.
Water is completely burnt hydrogen.
You can see in the formula that the hydrogen has combined so well with the oxygen that they formed one formula H2O.
See also
...
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Answer to:
Can anyone tell me in plain English how to use a tubular inside micrometer?
Assume we're measuring a horizontal pipe which we're looking along.
Place the micrometer in the pipe vertically with the "number" end up. Extend the micrometer until it's nearly as wide as the hole. Keep the bottom of the micrometer in one place.
You can tell when the micrometer is not extended enough if you can rock it from right to left in the pipe.
You can...
Answer to:
(x^(2)-2y^(2)=1)
What a lovely hyperbola...
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Answer to:
Is O- a common blood type?
In West Europe and the USA, the proprotions are roughly:
37% O+
36% A+
8% B+
3% AB+
7% O-
6.5% A-
1.5% B-
1% AB-
Making O- not particularly rare, occuring in one in 14 people.
(Note: recessive doesn't necessarily imply rare)
Answer to:
I have an isoceles triangle and the slope is 2/3 and the line in the middle is 10ft how can i find the base?
Is the "line in the middle" the vertical "altitude" of the triangle? If so,
Slope = 2/3 means "up 2ft vertically for every 3ft across horizontally".
If you go up 10ft vertically, you go across 15ft horizontally.
That gives you half of what you need to solve this question. The rest is up to you.
Answer to:
How many rectangles in a grid of 30 rectangles (6 by 5)
First think of a grid of 6 by 1 above the main grid:
A rectangle can be six wide in one position, or five wide in two positions, or ...
= 6*1+5*2+4*3+3*4+2*5+1*6
= 56 rectangles
Now a grid of 1 by 5 to the left of the main grid:
= 5*1+4*2+3*3+2*4+1*5
= 35 rectangles
In the grid itself, there is a rectange for every combination of a rectangle from the top grid and the left grid.
=...
Answer to:
Two partners divide a profit of $2000 so that the difference between the two amounts is half of their average. What is the ratio of the larger to the smaller amount?
You don't need the $2000, its not used in the answer:
Imagine the real number line with the two amounts A, B and the average M marked:
0 ... A .. M .. B ... ->lots
M is exactly half way betwen A and B
half of M is mentioned as the distance between A and B. A to M is half that distance = a quarter of M.
from 0 to A must be three quarters of M.
0 to B must be five...
Answer to:
What is the best property of real numbers?
The most useful property of real numbers is that they contain the limit of all converging sequences (of rationals or real numbers). The "completeness" property.
This allows them to be used for roots of rational numbers and for differentiation and integration.
Some other properties:
Every polynomial of odd degree has at least one real root.
There are as many real numbers...
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Answer to:
Help me solve this question, please show all proving- thanks! In triangle ABC, the angle B is obtuse, angle A= 9 degrees, AC= 12cm and BC= 2cm. Calculate angle ABC and AB. (Answers: angle ABC= 110 degrees 11minutes and AB= 11.16cm)
Alternative names for the sides are 'a' for side
opposite angle A, 'b' for the side opposite B and 'c' for the side opposite C.
You have b = 12 and a = 2 and A=9 and you want B and c.
Cosine rule says:
a^2 = b^2 + c^2 - 2 b c cos A
Filling in the values of a, b, and cos A gives you a quadratic equation for c, which you cansolve.
For B you can use the...
Answer to:
Why is the velocity of sound greater in water than in air?
To say its because water is denser or that the molecules are closer together explains nothing.
In fact, if you were to plot the speed of sound against density for various materials, you certainly don't get a straight line.
It wouldn't matter how close together molecules were if the motion of one molecule could not affect the next.
The speed of sound in a medium is related to...
Answer to:
Do you think Global Warming is a scam?
Global warming is happening.
It is happening at an unprecedented rate.
This rate coincides with the growth of heavy industry.
A reasonable explanation for the accelerated rate is that much of it is caused by the extra carbon dioxide production caused by burning of fossil fuels, which causes a greenhouse effect, trapping in heat.
Is it a true explanation? It is certainly far more...
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Answer to:
What is the unit of measure that determines shoe size?
"English sizes": barleycorns:
child : last length in barleycorns - 12
adult : last length in barleycorns - 25
A barleycorn is an old unit: literally the length of a corn of barley. Now standardized on one third of an inch.
(example size: adult size 12 = 37 barlycorns = 12.33")
A last is the "wooden foot" around which a shoe is made.
USA sizes use the same...
Answer to:
MHAE09 HOW COMMETS HAVE A TAIL?
MHAE09?
COMETS have a tail because some of the stuff they are made of is boils when it comes near the Sun, and is blown away by the solar wind. Some of the loose stuff is blown away too. That is why the comet tail is always on the opposite side of the comet to the Sun, so the comet appears to move backwards as it leaves the Sun, face to sun, tail in front.
Answer to:
How do I write an equation of a line in slope-intercept form with the slope of -2/5 and y-intercept (0, -3)?
You just remember that slope intercept form is like:
y = m x + b
where m is slope and b is the value when x=0
Answer to:
Let f(x)=4sin(x+pi/5). What is the period of f?
a 1/4
b 4
c 2pi/5
d 10pi
None of the above, curiously.
But perhaps you meant 4 sin ( (x+pi)/5)
sin has a period of 2pi
sin(x) = sin(x + 2 pi)
f(x)
= 4 sin( (x+pi)/5) ) = 4 sin ( (x+pi)/5 + 2 pi)
= 4 sin ( (x+ pi + 10 pi)/5)
= 4 sin ( ((x + 10 pi) + pi) / 5)
= f(x + 10 pi)
which says we get the same answer if we add 10pi to x
Answer to:
In a group of cown and turkeys, the number of heads in 35 less than the number of legs. What is the largest number of cows that could be in this group of animals? Show reasoning.
The largest number of cown is if you have as many as possible.
They can't all be cown, because on cown, legs-heads= 3 per cow. and 35 is not divisible by 3.
But for a turkey: legs-heads = 1
So the problem is now: make 35 with as many 3s as possible and make the rest up with 1s.
Answer to:
I'm trying to find the "zeros" of this polynomial. To get them I need to factor: -2x^3-x^2+x. How can I factor this???? Please help.
You see each term has a factor of x, so x can be taken out:
x(-2x^2-x+1)
Now to factorize: -2x^2-x+1
You say you have found one of the roots is x=-1
which makes one of the factors (x+1) which is zero when x=-1
There is a way you can use that to take out the (x+1) factor leaving a simpler polynomial:
There are two ways to do that, either using "long division" where you...
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Answer to:
On a certain 20 question test, a student receives 4 points for each correct answer, loses 3 points for each incorrect answer, and loses 2 points if no answer is given. Todd took the test and scored 34 points. How many problems did he answer correctly?
This problem is harder than it looks, it's a diophantine equation.
The correct answers score 4
Answers which are not correct score -2 or worse
Let C be the number of correct answers.
(20 - C) is the rest of the answers.
We know 4 C - 2 (20 - C) is equal or greater to Tom's actual score because I've only taken off two points for each non-correct answer, even if he got...
Answer to:
What is surface area used for?
Working out how much paint you need.
Surface areas don't come up that often.
How much plastic do you need to make a bottle? it's roughly surface area times thickness.
Surface area also comes up when you do radiation: How much sunlight falls per square meter, for instance.
Answer to:
Using only six points, how can you draw four different lines with each line containing at least three points?
Draw a square of points. You can obviously draw four infinite lines at right angles through two points each.
I've still got two points left. I just need to arrange to place these points so each lies on a pair of the lines, and I'll have four lines each with three points, and six points in all.
So draw a four sided shape which is approximately square but where no two sides are...
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Answer to:
What do you think is the name of this salt; White solid, soluble in water but doesn't conduct electricity in water and is insoluble in ethanol and doesn't conduct electricity in ethanol?
EDIT: Sorry, misread the question. Please flag.
Answer to:
How big is a kilogram of bacteria?
Like most living stuff, bacteria are mostly water.
The density of water is 1kg per liter.
So a kg of bacteria is about a liter - very roughly a four inch cube.
Answer to:
Does anyone else think there are way too many first year college chemistry students trying to get there homework done on AB?
No.
...
Questions are questions.
Answers are answers.
Answer to:
Function Notation: If f(x) is a linear function and f(1)=3, and f(-1)=5, find f(4)
On a graph, the two points you have are:
(1,3)
and
(-1,5)
Slope is constant on a linear function and is given by
(y2-y1)/(x2-x1)
= (5-3)/((-1)-1)
= 2/-2
= -1
(Or just note that y decreases 1 for each unit of x)
Your new data point must match the same slope:
(y - 3) / (4 - 1) = -1
y - 3 = -3
y = 0
Check: x=-1 to 1 changed y from 5 to 3. At a slope of -1, three more units...
Answer to:
Do you need a calculator to solve simple arithmetic?
sorta. I can do the arithmetic, but I'm never sure it's right without the calculator. This all stems from being allowed to use a calculator in an exam. Before that I was always 100% confident of my answers!
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Answer to:
Can you tell me the formula to find the distance from 0,0,0 to x,y,z and define every "tool" used in it except + - ( ) ^ x / =
Well it's sqrt(x^2 + y^2 + z^2), so you might mean 'sqrt'
For this purpose sqrt(A) is defined as that non-negative number B where B*B = A.
Alternatively, the distance is given by the L2 norm, which is given by the square root of the scalar product of the distance vector with itself.
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Answer to:
Three young boys have total age of 24. Answer the following questions with proper calculation steps and explanation.
If standard deviation of the ages is 2, and the age of one of the boys is 8, what is the age of the oldest boy of the three?
Mean age = total age / number of boys
= 24/3
= 8
standard deviation is the root mean square average distance from the mean.
Let the boys (signed) distances from the mean be d1, d2, d3, so that their ages are 8+d1, 8+d2 and 8+d3
Their total age is 24+d1+d2+d3 so d1+d2+d3 = 0
Then you have sqrt((d1^2 + d2^2 + d3^2)/3) = 2
d1^2 + d2^2 + d3^2 = 12
And you also know that...
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Answer to:
Three young boys have total age of 24. Answer the following questions with proper calculation steps and explanation. If standard deviation of these boys’ ages is 0, what is the age of the oldest boy of the three?
Standard deviation is a measure of the average difference of the values from the mean.
It's a "root mean square" average.
If the average difference of the boys ages from the mean is zero, then the difference of any particular boys age from the mean must be zero.
In other words, all three boys have the same age as the mean, and therefore as each other.
Three boys, same...
Answer to:
What is the exact value of cos(pi/4-pi)?
pi radians = 180 degrees.
in degrees:
cos(45 - 180)
= cos(-135)
It helps to draw a graph of cos and sin at this point.
Referring to the graph:
cos(x) = sin(x+90)
sin(x) = -sin(-x)
so cos(-135) = -sin(45)
Draw a right triangle with legs sqrt(2) and sqrt(2).
The angle is 45.
The hypotenuse is 2 by Pythagoras.
sin(45) is sqrt(2)/2 by SOHCAHTOA.
So cos(-135) = -sqrt(2)/2
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Answer to:
Let f(x)=4sin(x+pi/5). What is the period of f?
Period of 4sin(x+pi/5)
is the same as the period of sin(x+pi/5)
is the same as the period of sin(x)
Adding 'pi/5' just shifts the graph to the left, so that it starts further on in the cycle compared to the old graph. It doesn't affect the period.
The period of sin(x) and cos(x) is two pi radians.
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Answer to:
How do you divide two fractions e.g 1/6 of 3/4?
"of" means MULITPLY not divide.
1/6 of 3/4 is (1/6) times (3/4)
= (1 times 3) /(6 times 4)
= 3/24
= 1/8
You could see this a different way:
3/4 is three quarter-size pieces of pizza.
But pizza more often comes in eighth-size pieces.
3/4 would be six eighth-size pieces
And one sixth of that, would be a single eighth-size piece.
DIVIDING fractions is when someone...
Answer to:
The probability of stock A rising is 0.3; and of stock B is 0.4. If stocks A and B are not independent, and the probability of both stocks rising is 0.09, what is the probability that neither stock rises?
The four possibilities are:
A rises, B rises (probability 0.09)
A rises, B doesn't rise
A doesn't rise, B rises
A doesn't rise, B doesn't rise (probability to find).
The sum of the first two events, which are exclusive is given as 0.3, so the second event must have probability 0.3-0.09 = 0.21
The sum of the first and third events, which are exclusive, is given as...
Answer to:
The probability of a successful merger with a larger firm is 0.40. Given that a merger is successful, there is a 0.25 probability that profits next year will be high. What is the probability that both the merger will succeed/profits will b
P(A and B) = P(A) * P(B | A)
B | A is pronounced 'B given A'
If A = merger successful.
and B = profits high.
We're told P(A) = 0.4
and that P(B | A) = 0.25
So P(A and B) = 0.4 * 0.25 = one quarter of 0.4
Answer to:
Find the coordinates of the points that divide the line segment joining (4,5) and (10,14) into three equal parts. Translation? Segment joining?
The coordinates of the points that divide the line segment into three equal parts are the coordinates that divide the intervals x=[4,10] and y=[5,14] into three equal parts.
The x interval is 6 so the coordinates are every 2 units:
4,6,8,10
The y interval is 9 so the coordinates are every 3 units:
5,8,11,14
The points are (4,5),(6,8),(8,11),(10,14)
Answer to:
How do you integrate xcos(x^5) wrt x?
cos(z) = (e^(i z) - e^(-i z))/2
That makes x e^(i x^5)/2 - x e^(-i x^5)/2
So to be able to integrate z = x e^(k x^5) is enough to do this one.
put u = - k x^5
x = (-u/k)^(1/5) = (-k)^(-1/5) u^(1/5)
dx/du = (1/5) (-k)^(-1/5) u^(-4/5)
z = (-k)^(-1/5) u^(1/5) e^(- u)
Integral z dx = Integral z (dx/du) du
= (1/5) (-k)^(-2/5) Integral u^(-3/5) e^(-u) du
This integral is a...
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Answer to:
Which of the following statements are true? {16}∉ {13, 14, 15, 16, 17} {16}∉ {{13}, {14}, {15}, {16}, {17}} Ø = { }
You're question's missing some symbols.
{16} - can't tell what the question was.
{13,14,15,16,17} ??? {16}
This question is true if ??? is the sign for "superset of".
{{13}, {14}, {15}, {16}, {17}} ??? Ø = { }
This question is true if ??? is the sign for "set intersection"
Answer to:
Suppose that you have a three ounce glass, a five ounce glass, and an eight ounce glass. The two smaller galsses are empty, but the largest glass contains eight ounces of milk. How can you divide the milk into two equal parts by using only these three gla
A=8oz
B=5oz
C=3oz
fill B from A: 3oz in A, 5oz in B, 0oz in C.
fill C from B: 3oz in A, 2oz in B, 3oz in C.
fill A from C: 6oz in A, 2oz in B, 0oz in C.
fill C from B: 6oz in A, 0oz in B, 2oz in C.
fill B from A: 1oz in A, 5oz in B, 2oz in C.
fill C from B: 1oz in A, 4oz in B, 3oz in C.
fill A from C: 4oz in A, 4oz in B, 0oz in C.
I claim my five dollars.
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Answer to:
Let f(x)=sqrt x-4 and let g(x)=x^2. What would g(f(8)) equal?
f(x) = sqrt(x)-4 or sqrt(x-4) ?
g(f(8)) is g(x) with f(8) written in place of x.
So: g(f(8)) = (f(8))^2
You'll have to decide what f(8) should be.
Answer to:
The length of arc AB is 5pi/6 meters. What is the area of the shaded region?
What shaded region, and what's the radius?
If the radius is r meters, then the angle subtended by the arc is 5pi/6r radians, which is 150/r degrees.
If the shaded region is the shape of piece of pie, then its area is given by (1/2) alpha r^2 where alpha is the angle in radians.
So for a radius of r that would make the area: 5 pi r/12
Answer to:
Whats the answer to solve the inequality 6(4-3x)+3x<4(8-3x)
6(4-3x) + 3x < 4(8-3x)
6*4 - 6*3x + 3x < 4*8 - 4*3x
24 - 18x + 3x < 32 - 12x
0 - 18x + 3x < 8 - 12x
0 - 0x + 3x < 8 - 12x + 18x
0 - 0x + 0x < 8 - 12x +18x - 3x
0 < 8 + 18x - 15x
0 < 8 + 3x
-8 < 0 + 3x
-8 < 3x
-(8/3) < x
or
x > -(8/3)
Answer to:
Suppose you have written down all the numbers from 1 to 19,000. What is the total number of fours you have recorded?
Every ten numbers you find a four in the last place
So thats 1900 fours from the last place.
Every hundred numbers you have ten fours from the tens digit. So that's 1900 fours from the tens digit.
Every thousand numbers you'll have 100 fours from the hundreds place (for numbers ending with 400 to 499)
So that's 1900 fours from the hundreds place.
Every ten thousand...
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Answer to:
Seven people plan to meet after school, and if they all show up, there will be one group of seven people. However, if only three of them show up, in how many ways is this possible?
The number of ways of choosing three people from seven is given by "7 choose 3" sometimes written 7C3 which is calculated like this:
(7*6*5)/(3*2*1)
Answer to:
How many grams should 1.0 mg/kg be administered in a 150 lb patient
Go to google, type
(1.0 mg/kg) * 150 lb in grams
in the box.
be amazed.
(0.068 grams)
Answer to:
In calculus, What is an anti-derivative?
An anti-derivative is any function which has a given derivative.
Given that the derivative of a function f(x) is 3 x^2,
one antiderivative for this derivative would be the function f(x) = x^3 - 5, because this is a function which has 3 x^2 as a derivative.
Given one antiderivative F(x), F(x) + C is another.
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Answer to:
Yes or no, is the answer to this question no? (YES OR NO ONLY!!)
YES OR NO
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Answer to:
A 1542 kg car moving E @ 12 m/s strikes a 875 kg car moving S @ 17 m/s and the cars stick together. How do I find the direction and speed of the wreck immediately after the collision?
Use the conservation of momentum.
The sum of the momentums must be the same before and after, when you take into account the directions.
momentum = mass * velocity
so your working will look something like:
m1 * v1 + m2 * v2 = (m1 + m2) * v3
Answer to:
A man was shot at the proximal part of the axillary vein which causes profusing bleeding. discuss other dangers he will also be facing at this time of the injury
There's the mad man with the gun.
Answer to:
What will happen to earth if water is not polar?
Water would be a gas at room temperature.
Dry earth.
Answer to:
Why are there more carbon compounds than silicon compounds on earth?
Interesting question.
I will guess that it is because of life.
There are few silicon compounds because the silicon holds tightly onto oxygen and won't let go.
If the same happened with carbon you'd get carbon dioxide. But carbon dioxide is used by plants to build structure, giving off oxygen. There's a lot of free oxygen on our planet, and nearly all came from the...
Answer to:
Is anything shinier than gold?
A mirror.
Answer to:
The Earth rotates about its axis because living things need an Alternation of Light and darkness. Question is: Is this an hypothesis or not?
It is a hypothesis if you can test it.
Most of the other answers miss the point. A hypothesis is NOT something which is known to be true, but something that can be checked.
I think it would be difficult to test. There is a lot of circumstantial evidence that the hypothesis is false: for instance, other planets revolve even those that certainly do not have life.
But to test this...
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Answer to:
Why does the snow around a tree melt faster than when there are no trees around?
I would guess it is because a forest acts like a blanket, and keeps the heat out, whereas a sole tree is exposed to whatever heat is available.
A blanket can keep in warmth or cold.
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Answer to:
What's up with all the prime number questions?
Their frequency.
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Answer to:
I have a box of pens, equal parts red and blue. I reach in and grab three pens at once. What are the chances of at least one of them being red if the box has (a) 14 pens, (b) 140 pens, and (c) infinity pens? Please explain your calculation.
The number of ways of choosing three arbitrary pens from n items is "n choose 3" which is the binomial coefficient nC3
The number of ways of choosing 3 blue pens from a box containing n red and n blue pens is nC3 using the same reasoning.
Therefore if you subtract these you get the number of ways of choosing at least one red pen:
If the box has 2n pens, then the number of...
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Answer to:
What is the importance of a dependent variable and an independent variable in a research study?
The dependent variable is presumed to depend on the independent variable.
By changing the independent variable, you can estimate its effect on the dependent variable.
There can be other variables which have to be kept constant during the experiment. These are called controlled variables.
Answer to:
If a family has 8 children, in how many ways could the parents have 4 boys and 4 girls as children?
That depends on what you mean by a "way" of having children.
Some of the more obvious answers:
One. Four boys and four girls, there's no other way of getting that many boys or that many girls.
40320. Usually each child has its own distinct DNA. The information in DNA can be converted into a number, and there are 8-factorial = 8! = 40320 orderings for eight numbers.
...
Answer to:
How do you write 45 in Roman numerals?
This is conventionally written:
XLV
But the Romans themselves would originally have written:
XXXXV
or *any* combination which sums to 45, such as XIVIVVIVIX
if it is convenient.
The idea of "XL" meaning 40 would originally have been regarded as stupid and incorrect to a Roman. Start with XL and take away the X and you'd end with more than you started with!
However, the...
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Answer to:
What is inertia?
Inertia is a measure of a body's resistance to motion.
Linear inertia gives the body's resistance to linear motion and is given by force applied divided by acceleration produced.
Linear inertia turns out to be identical to mass.
Moment of inertia is a measure of a body's resistance to turning.
Take a cylinder with a square cross-section (when you cut along the axis)...
Answer to:
I need help in this question? A nuggetof gold with a mass of 521g is added to 50.0 ml of water. The level of water rises to a volume of 77.0ml. What is the density of gold? I need the formula, and If you could show me how you solved it. thanks
desity = mass divided by volume.
77ml = 50ml of water + 27 ml of gold.
27ml = volume of gold.
density of gold = 521/27 grams per ml.
= 521/27 grams per cubic centimeter.
Answer to:
What type of blood did Jesus have?
red
Answer to:
Can someone explain to me how to slove this equation? (2x + 3)(3x + 1) i dont want the full answer just tips. thanks
It isn't an equation. An equation is an expression containing an equals sign.
"solve" can also means to find when something is zero.
So you would find x for which (2x+3)(3x+1) = 0
This happens when either (2x+3)=0 or (3x+1)=0
leading to x=-3/2 or x=-1/3
Given (2x+3)(3x+1) on its own, the most likely thing you'd be asked to do with it, is expand it.
Here's...
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Answer to:
I need help with factoring polynomials...I know you have to put the GCF on the outside of the parenthesis, but what determines its variables and exponents?
Generally factoring polynomials is hard.
For quadratics, you can use the middle term method, completing the square, or the quadratic formula.
For factoring polynomials at school, there is the grouping method: you can group the terms into n sets of m terms, where each set of m terms has a common factor.
Is this the method you're using?
You can also try evaluating the polynomial...
Answer to:
What benefit(s) to life on Earth has Jupiter provided?
It is often said that Jupiter protects us from errant asteriods and rocks by capturing them in its orbit, but a recent study showed that the opposite may be the case, that there are probably marginally more impacts on Earth due to Jupiter altering orbits of rocks rather than less.
But an impact could be considered a benefit too - we wouldn't be here if the dinosaurs hadn't died...
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Answer to:
What type of chemical reaction starts with 1 compound that breaks down?
A decay reaction ... which will often be a first order reaction.
Answer to:
How do you integrate (sinx)^5 wrt x?
(sin x)^5 = (sin x)^2 (sin x)^2 (sin x)
now I can change all but one of the sins to coses:
(sin x)^5 = (1-(cos^2 x))(1-(cos^2 x))(sin x)
and now I can integrate by using change of variable to
y=cos x
dy = -sin x dx
Integral (1-y^2)(1-y^2) (-dy)
Integral (-1 + 2 y^2 - y^4) dy
= -y + (2/3) y^3 - (1/5) y^5 + C
= -(cos x) + (2/3) (cos x)^3 - (1/5) (cos x)^5 + C
is a solution.
...
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Answer to:
I want to calculate the length of the tangent common to two arcs with radius R1 and R2. Can anyone help me?
Thanks in advance.
Draw the two arcs.
Let O be the center of the larger arc, and Q the center of the smaller arc.
Draw the tangent touching the arcs at A on the larger arc and B on the smaller arc.
Join AO and BQ
Draw a line through Q parallel to the tangent and crossing OA (or OA extended) at X
You can probably see what the length of OX must be.
And the angle QXO.
And you probably know OQ.
And then you...
Answer to:
Which one of the following statements is characteristic of liquid water? it has a definite volume but not shape, it has a definite volume and shape,it has a definite shape but no volume, or it has neither definite shape or volume
clues:
clue 1:
water is often measured in cubic centimeters and pints, which are measurements of volume. Does a given amount of water retain its definite volume? Or does liquid water expand to fill the space available, causing everyone in the room to drown?
clue 2:
When you pour out liquid water, does it change shape? Or does it always stay the shape of the container it came from?
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Answer to:
What are celestial bodies
celestial means "in the sky"
celestial bodies are naturally occuring things that you see in the sky, particularly at night, such as the moon and planets, nebulae, stars and galaxies.
Answer to:
Reactant and product in a burning candle
wax(high value alkanes) + oxygen -> carbon dioxide + water(steam)
Answer to:
How many stars are in our solar system?
One.
It's that big thing in the middle with the glare to it.
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Answer to:
What is the smallest unit?
gram
milligram
kilogram
decigram
microgram
gram = 1 gram
milligram = 0.001 gram
kilogram = 1000 gram
decigram = 0.1 gram
microgram = 0.000001 gram
I'm putting my money on the last one.
Check : http://en.wikipedia.org/wiki/SI_prefix
Answer to:
Sequence 1, 5, 17, 53, 161
the sequence is
1
add 4
add 12 = 3*4
add 36 = 3*12
add 108 = 3*36
add 324 = 3*108
which gives 485
A formula for the ith entry is
1 + 2 (3^(i-1) - 1)
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Answer to:
This isn't homework, I just want my friends to think I'm smart. Its Trig, so only answer if u know what ur doing please. Find all solutions of the equation in the interval {0,2pie}. cos x/2 - sinx = 0.
A grapher will give you a rough answer:
http://www.walterzorn.com/grapher/grapher_e.htm
put cos(x/2)-sin(x) in the large box, replacing what's there.
Change x min to 0 and x max to 6.283
You can see from the graph there are three solutions in that range and one is pi, which fits because cos(pi/2)= 1 and sin(pi) = 1
For the other two solutions you'll need some more...
Answer to:
How do I find the element of Pascal's triangle at row x element y
This is also called the binomial coefficient and is sometimes written nCr where n is the row starting at zero, and r is the element index on the row, again starting at zero.
[So you actually want the number (x-1)C(y-1)]
There are a number of ways of finding nCr
One is that if n=r or r=0 then nCr = 1
otherwise nCr = (n-1)C(r-1) + (n-1)Cr from which you can find all the entries.
...
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Answer to:
What is the next number in the following sequences?
3 9 5 25 1?
2 7 11 14 16?
10 6 20 12 40?
18 15 5 39 36?
First one is pairs (a, a^2)
Second one: add 5, add 4, add 3, add 2, next is add 1.
Third one: each pair of numbers is doubled like
a,b,2a,2b,4a,4b
Fourth one: not sure, but it could be triples a,a-3,(a-3)/3 making the next number 36/3 = 12
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Answer to:
Starting at 1 = (4+4) / (4+4) how far can you go before reaching a number you can't make with just four 4's?
If you are allowed
decimal point, square root, factorial, + - * / ( )
and you HAVE to use all four fours, then the first number you can't make is 73
If you can use logs and square roots you can make any natural number you like.
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Answer to:
What is the total weight of the earth?
The MASS of the earth is about
5 974 000 000 000 000 000 000 tonnes.
(and 1 tonne is roughly the same as 1 ton)
but the Earth is in free fall.
And the WEIGHT of a body in free fall is ZERO!
Weight is a measure of how hard the floor pushes up on something to stop it falling. Nothing's stopping the earth falling, so it has no weight!
Believe it or don't.
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Answer to:
How can scientists make predictions of what break through they'll make at C.E.R.N. in the next decade? For example the Higgs boson.
The "standard model" of physics works very well but there are embarassing holes: the bare theory predicts that matter has no mass, which is obviously wrong.
The Higgs Boson is a made up mechanism which explains how other particles might gain their mass which seems to fit the facts, but the Higgs Boson has not been discovered yet. Physicists think it it is the explanation most...
Answer to:
I hate to admit this.... My 8 year old is trying to come up with an idea of how to produce heat by mixing two things together, and I am at a loss! Any ideas? Searched the web unsuccessfully. Thanks.
"plaster of paris" and water.
Answer to:
Suppose that f(x) = -8x 6 and that g(x) is perpendicular to f(x) and passes through the point (0,6). What is g(8)?
Your question is incomplete.
What you need to solve your question:
The slope equation:
m=(y2-y1)/(x2-x1)
gives the slope on a particular line for any two different points (x1,y1) and (x2,y2) on it.
And you also need to know that if two lines are perpendicular, their slopes multiply to make -1
Answer to:
If f(x) = x3 + 2 and g(x) = x + 3, what is f(g(x))?
I suspect you meant
f(x) = x^3 + 2
f(g(x)) is just writing g(x) in place of x:
f(g(x)) = (g(x))^3 + 2
and g(x) is x+3 so
f(g(x)) = (x+3)^3 + 2
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Answer to:
If the line Y=m x+b is tangent to the circle
x^2 +y^2=r^2. What is the equation of that circle relating to m, b, and r?
Let's find the point (x,y) where the line touches the circle.
(x,y) must satisfy the line equation y=mx+b
They must also satistfy the circle equation x^2 + y^2 = r^2
and the line joining (x,y) to the center of the circle must be at right angles to the tangent line.
The line joining x,y to the center of the circle has the slope (y/x)
The line equation must have a perpendicular slope.
...
Answer to:
What number goes in the blank? 823543 46656 3125 256__41
823543=7^7
46656=6^6
3125=5^5
256=4^4
27=3^3
4=2^2
1=1^1
EDIT: I'd love to get some opinions on why this was downrated!
Answer to:
A cone is circumscribed about a sphere with fixed radius a. If r is the radius of the base of the cone, express its volume as a function of r?
I've answered a very similar question to this here: http://www.answerbag.com/q_view/963727
Draw a line from the center of the circle, O, to a point P on the tangent circle where the cone touches the sphere.
Let A be the apex of the cone.
Extend the line AP to meet the base at B.
Let F be the point on the base immediately below O
OP = OF = a
FB = r
tan OFB = tan OPB = a/r
angle...
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Answer to:
4/7
----
5/8
Does anyone know how to solve this math problem?
It depends what you mean by '----'
Is this a 'fill in the blank?'
In which case is the question looking for "less than" or something like that?
4/7 is the same as 32/56
and
5/8 is the same as 35/56
where 56 is a common multiple of 7 and 8.
so 4/7 is less than 5/8
Normally in math '----' would mean negative negative negative negative. And four...
Answer to:
Is there a symbol used for 'area', like delta is used for change/difference?
A for area.
d is also used for a change or difference.
An infinitesimal one.
(so oddly, s is often used for distance)
So dA would be an infinitesimal change in area.
Answer to:
A recent survey showed that about 8% of the folks living on the Upper East Side are overweight. A few blocks north, in so Harlem, over 30% are found to be overweight. Is this an observational study or an experiment?
On its own, I think its a study.
If it is to be an experiment, then there needs to be a hypothesis like: "we believe that the folks living in Harlem are more likely to be overweight than those in living in the Upper East Side" and then you do the survey to test the hypothesis to see if it is true.
Now you have the results of the survey, you still need to do some statistical...
Answer to:
USE GEOMETRIC TERMS TO DESCRIBE HOW A CIRCLE AND A SPHERE ARE DIFFERENT.
A circle inhabits a two dimensional Euclidean space.
A sphere inhabits a three dimensional Euclidean space.
The boundary/edge of the circle is a 1-manifold.
The boundary/surface of the sphere is a 2-manifold.
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Answer to:
An airplane flew for 4 hours with a 20-km/h tail wind. The return flight against the same wind took 5 hours. Find the speed of the plane in still air.
Let v be the speed of the plane.
On the way, the speed of the plane though the air is v.
The speed of the air is 20. The ground speed of the plane is v + 20
On the way back the ground speed is v - 20
Distance = speed times time both ways:
(v+20) * 4 = (v-20) * 5
80 = v-100
180 = v
distance must have been 800km
Answer to:
A baseball (m = 150 g) approaches a bat at a speed of 38.7 m/s, is hit straight back at a speed of 48.5 m/s. If the ball is in contact with the bat for a time of 1.27 ms, what is the average force exerted on the ball by the bat? Neglect the ball's weight.
Change in momentum = (48.5-(-38.7))*0.15
average rate of change of momentum = total change / total time = (48.5+38.7)*0.15/0.00127
But FORCE is rate of change of momentum
(it's actually the correct definition of force according to Newton, rather than our modern F=ma, which is an oversimplification)
Answer to:
A 50.0 kg swimmer is standing on a stationary 191 kg floating raft. The swimmer then runs off the raft horizontally with a velocity of +4.57 m/s relative to the shore. Calculate the magnitude of the recoil velocity that the raft would have(no resistance)
The total momentum starts at zero.
The total ending momentum is
mass_of_raft*raft_velocity + mass_of_swimmer*swimmer_velocity
These must be the same (conservation of momentum).
mass_of_raft*raft_velocity + mass_of_swimmer*swimmer_velocity = 0
191 * raft_velocity + 50 * 4.57 = 0
raft_velocity = - (50 * 4.57) / 191
Answer to:
Why is the sum of the nth row in pascal's triangle 2^n?
The 0th row is ... 0 0 0 0 1 0 0 0 0 ...
(I'm writing zeros for the blank spaces)
it has one '1' in the middle.
it sums to 1 which is the same as 2^0
in each row after that each number is the sum of the two numbers diagonally above it.
So each number in the row above is used twice.
So the sum comes to twice the sum of the previous row.
So the nth row is 2^n
This...
Answer to:
What do you best know me for? What would you best remember me for? Chris
I best know you for standing up for what is right and supporting the downtrodden, and uprating the answers that actually answered the question, for making things cheerful.
You were my best friend on AB.
I hope you return.
But if you don't, then enjoy the rest of your life, free of the trivialities of AB!
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Answer to:
Have you ever seen Chris make a good decision?
I've never seen Chris make a bad decision.
With the possible exception of disapparing recently.
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Answer to:
Once 1 boy asked 1 girl whats your name.girl said it was written in the no plate of my scooty 7.1 4.3 6.2 5.2 9.3 whats the name?
The name is PINKY
check your phone keypad.
Answer to:
Can anyone plz help me with my algebra homework, plz, message me at slayer6903@yahoo.com plz, and ty
Just ask them in Algebra, but make sure you make it clear that you've attempted them and where you are stuck, or some of the less bright amongst us will assume you are trying to cheat.
Answer to:
N = ?
0n = 1024
1n = 5120
2n = 11520
3n = 15360
4n = 13440
5n = 8064
6n = 3360
7n = 960
8n = 180
9n = 20
10n = 1
If you don't want to solve the whole thing, I'd be content with just your direction on HOW to solve it. Thanks!
I don't know what you mean by the terms 0(n), 1(n) etc.
The numbers you have given are 2^(10-i) nCi
where nCi is the binomial coefficient
This is what you get when you expand (2 + 1)^10
So perhaps the N you want is 3^10 or 59049
Answer to:
If I fall from a 3 story window (approx. 45 feet), what speed am I travelling (in mph) and how long will it take me to get from the window to the ground?
Equation: s = u t + (1/2) a t^2
where s = distance
u = initial speed ( zero here )
a = acceleration ( 9.8 m/s^2 )
45 feet = 13.716 m
13.716 = 4.9 t^2
t = 1.673 seconds
Equation: v = u + a t
v = final speed
v = 9.8 * 1.673
=16.3954 m/s
= 59023 meters per hour
= 36.68 mph
Answer to:
An objects response to an input or removal of heat is...
An increase or decrease in temperature, I think is the more obvious answer.
Answer to:
Your friend is wearing a blue jacket. Is the temperature of the jacket 10,000 K? What is the temperature of the jacket? Why then is the jacket blue?
The 10,000K is the "color temperature" or "black body temperature" of the jacket.
It doesn't mean that the jacket is 10,000K hot unless the jacket is naturally perfectly black.
A perfectly black body radiates a precise spectrum, which might look blue at a temperature of 10,000K
Non-black bodies reflect some light. During the day, the jacket looks blue because...
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Answer to:
What is the net force on a 90kg airplane flying at const velocity of 180km/h north? can any1 also provide the formula
F = ma
Force = Mass times Acceleration
Const Velocity = No Acceleration
Answer to:
When we apply DC voltage to a condutor it mean we are applying constant force,constant force means constant accelaration, constant acceleration means we will have an increasing current instead we get a constant dc current why?
Because the faster the electrons move, the harder it is to move them - the greater the resistance to movement.
They actually travel at an appreciable fraction of the speed of light.
An analogy:
When we apply gravity to a falling parachutist, it means we are applying a constant force. Constant force means constant acceleration. Constant acceleration means the paracutist comes down faster...
Answer to:
The perimeter of a rectangle is 384 meters, the length is 82 meters greater than the width, what is the length and the width?
Perimeter of rectangle = length + width + length + width
length = width + 82
Perimiter of rectangle = width + 82 + width + width + 82 + width
4 widths + 164 = 384
4 widths = 220
2 widths = 110
1 width = 55
length = width + 82
length = 55 + 82
length = 137
Check: 137+55+137+55 = 384
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Answer to:
Kay has 1 pair of yellow socks and 3 pairs of black socks. What is the probability that Kay picks up 2 matching socks one after the other to form a correct pair.
Please explain the process.
Kay walks into the room, decides she wants yellow socks and picks up a pair.
Or black socks.
Either way, she ends up with a pair.
Ok, suppose Kay is blind.
In 2/8 cases, Kay picks a yellow sock first, and then the chance of getting a pair is 1/7
In 6/8 cases, Key picks a black sock, and then the chance of getting a pair is 5/7
Total probability = (2/8)(1/7) + (6/8)(5/7)
= 32/56 = 4/7...
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Answer to:
How would you factor (2x(squared)+9x+5)? I'm stuck :(
You can sometimes use the "middle term" method described here:
http://www.answerbag.com/q_view/1126040
You look for factors of 2 times 5 = 10 which add to 9.
add to nine because 2*5 is positive.
Here though the factors are clearly supposed to be 1 and 10 which DIFFER by 9. So I think your question should have been: (2x^2 + 9x - 5) or (2x^2 - 9x - 5)
HERE the factors have to...
Answer to:
How much air does go thru the 200mm wide, round ventilation canal, when the air is moving inside the canal at the speed of 5m/s? How do I solve this?
In one second, a particle of air will move 5 meters.
So behind it, 5 meters worth of air must have moved into the pipe, to replace the air that has moved on.
The cross-section of the pipe is round, diameter = 200mm
radius = 100mm = 0.1m
area of a circle = pi r^2 = pi times (0.1 m)^2
= 0.0314 m^2
So the volume of air in those 5 meters that moved through in 1 second is
5m * 0.0314...
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Answer to:
"For what values of k does the function y=cos kt satisfy the differential equation 4y^n = -25y?" I don't even understand how it's a differential equation... Please help!
Is the 'n' in brackets?
y^(n) is different to y^n
y^(n) means y differentiated n times.
if y = cos kt
then y^(1) = - k sin kt
y^(2) = - k^2 cos kt = - k^2 y
so if n was 2 and k was (5/2) then this would work.
y^(3) = k^3 sin kt
y^(4) = k^4 cos kt
y^(5) = - k^5 sin kt
y^(6) = - k^6 cos kt = - k^6 y
so if n was 6 and k was cbrt(5/2) then this would work
In general,...
Answer to:
Can someone verify If I am correct that 0.4x+7≤ 1.2x-4 is
x=-6.87?
0.4x + 7 <= 1.2x - 4
subtract 0.4x from both sides:
7 <= 0.8x - 4
add 4 to both sides:
11 <= 0.8x
divide both sides by 0.8
11/0.8 <= x
55/4 <= x
Or x >= 55/4
Answer to:
An astronaut on a distant planet wants to determine its acceleration due to gravity. The astronaut throws a rock straight up with a velocity of 16.6 m/s and measures a time of 19.6 s before the rock returns to his hand. What is the acceleration?
Let negative mean up.
The rock started with v=-16.6
It ended with v=+16.6
It changed by +33.2 m/s, in a time of 19.6 s
The average acceleration
= total change in velocity divided by total time
= +1.69 m/s^2 (down)
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Answer to:
What meaning to you think you could give to the decimal number 1.23 in terms of the distance idea of the real line? What would you do with 1.732050807568877293527?
If that number is supposed to be the square root of 3, then:
Draw the number line.
Draw a line 'A' perpendicular to the number line passing through 0
Draw a circle 'B' of radius 2, with center at 0.
Draw two circles 'C' and 'D' of radius 2, with centers at the two places where B and and A cross.
C and D intersect B at two places each.
Pick the...
Answer to:
I want that this equation 1000*(Cosh(x/1000)-1) connects two data points (0,50) and (60,80) how do i know how many shifts is neccesary to x?
What do you mean by shifts?
If you shift the equation 50 units up the y axis by 50 it matches pretty well, giving (60,82.02) rather than (60,80)
Answer to:
Hey frnd this is pratap frm orissa,can someone tell me about division algorithm
For any a and non-zero d, There exist unique integers q and r such that a = qd + r and 0 ≤ r < |d|, where |d| denotes the absolute value of d.
It says when you divide a by d, you get a unique quotient and remainder.
It becomes more useful when you start using it for more complex things than just numbers.
For instance, for any polynomial a and non-constant polynomial d there exist...
Answer to:
Does any one know how to give the solution set of this equation 1/7x>1/15? I am not sure about the answer I got.
The problem leads to x < -1/105
I'm trusting that you know how to get that far.
Then a set is written in {}
Either you write out every value that satisfies the problem, for example, like {2,3,4}, or you write something like:
{ x | x is even }
which means all those x for which x is even.
In your case the set is written:
{ x | x < -1/105 }
But if you fancy being a bit...
Answer to:
What is the answer to 12a squared over 24a squared minus 18a?
There are a number of possible answers to this.
The problem is that when you read out a math formula, you lose some of the "order of operations" information.
For instance, if I say "five over four minus three"
am I reading out an equation like: "(5/4) - 3" or "5/(4-3)"
So picking one interpretation of your question the answer is (1/2) - 18a.
...
Answer to:
Does 1 count as a prime number?
1 used to be considered a prime number, but doing so makes a mess of the Fundamental Theorem of Algebra, which states that any positive integer can be written as a product of primes which is essentially unique.
The prime numbers then give you a unique fingerprint for each number.
If you allowed 1, then you can multiply by any number of 1s so the decomposition into primes is not unique.
...
Answer to:
Is there such a thing that has an odd of once in infinite?
Yes. It's the same as "Probability of zero"
A probability of zero paradoxically doesn't mean that something is impossible.
For instance, if a random real number is chosen in the interval [0,1] then the probability of it being any specific number is zero. But do the experiment, and you find that you DID pick a specific number, despite the fact that the probability of...
Answer to:
How do you find Σ [i = 1 to n] for i^3, i^4, i^5, i^6.........i^9 by sheer mental power not from some table
o) If you're doing them in order, then
i^5 is i times i^4
so each time you multiply by i, starting with
i^0 = 1
i^1 = i times i^0
i^2 = i times i^1
and so on.
o) But say you want a specific power like i^23
Find
a=i^2
b=a^2 which is i^4
c=b^2 which is i^8
d=c^2 which is i^16
now 23 = 16 + 4 + 2 + 1
so i^23 = d * b * a * i
o) You can also sometimes use the...
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Answer to:
Could 10cm 24cm and 34cm be the lengths of a triangle
Depends on how you define 'triangle'.
If a triangle is three different points joined by line segments, then yes, but in this case the area will be zero and the triangle will be degenerate.
If a triangle is three non-colinear points joined by line segments, then no.
Answer to:
What is the limit x-->o x^2cos(4x)
cos always fits between -1 and 1 inclusive.
so x^2 cos (4x) is always between -x^2 and x^2 inclusive.
setting delta = sqrt(epsilon) will then satisfy the definition of "limit", making the limit zero.
Answer to:
A particle moves such that its position vector is given by r = (4t2) I + (2t2) j. Determine the normal & tangential components of the particles acceleration when t = 2 sec
In vector notation:
r = (4 t^2 , 2 t^2)
r ' = ( 8 t , 4 t )
r '' = (8 , 4)
at t=2
r ' = (16 , 8) which is in the direction:
(2/sqrt(5), 1/sqrt(5))
The component of the acceleration tangential to the motion is
(8 , 4) scalar product with (2 , 1) / sqrt(5)
= 4 sqrt(5)
The normal component is in the direction (-1/sqrt(5), 2/sqrt(5) (in 2 dimensions)
=...
Answer to:
Please give a full list of possible combinations using the numbers 1,4,5,8 using numbers 1 & 5 twice.
There is not enough info here.
What do you mean by 'a combination'?
If you want a four digit number you can't use the numbers 1 4 5 AND 8 and yet use 1 and 5 twice at the same time.
So, perhaps the combinations you want look like this:
114558
114585
114855
115458
115485
115548
115584
and so on.
There will be 180 altogether like that.
Answer to:
What is the sum of the all the odd numbers from 1 - 99 ? Is it (50/2)(100) ? I know that the first column gives 25, the second gives 75, the third gives 125, fourth is 175, fifth is 225, sixth is 275.....
Add them up like this:
1 + 99 = 100
3 + 97 = 100
5 + 95 = 100
...
49 + 51 = 100
So each pair of numbers adds to 100.
You only need to know how many pairs there are.
Well there are 100 numbers from 1 to 100
and I only used half of those = 50
= 25 pairs.
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Answer to:
1 gallon equals
eight pints.
Answer to:
Logic Puzzler: My favorite # is one of the following...5, 12, 7, one of the above, none of the above, or 6. If there is only 1 right choice, which one is it? I had fun with this, maybe you will too.
Using your own logic your favorite number cannot be:
5 (because then both "5" and "one of the above" are true)
12 (because then both "12" and "one of the above" are true)
7 (because then both "7" and "one of the above" are true)
6 (because then both "6" and "none of the above" are true)
"one of the...
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Answer to:
How do i work out 22% of 411.90?
22% means 22 percent means 22 per hundred means 22 hundredths
one hundredth of 411.90 is 4.119 (one for every hundred)
22 hundredths of 411.90 is 22*4.119
Answer to:
Why the line x=4 is a vertical line.
the x coordinate measures the horizontal displacement of a point. If the horizontal displacement is always the same for all points on a line, then the line can only be vertical.
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Answer to:
A combination of segments lenghts that do not make a triangle
1,2 and 20001020432
Answer to:
Easiest formula for this sequence: 1, 4, 10, 20, 35, 56, 84, 120, 165, 220, 286, 364, 455, 560, 680, 816, 969, 1140, 1330, 1540, 1771, 2024, 2300, 2600, 2925, 3276, 3654, 4060, 4495, 4960, 5456 Express in just a formula like a(n) = ~~~~
a(n) = (n+2)C3
where nCr is given by n!/((n-r)! r!)
EDIT: I can now see the 'This question relates to' link, which tells me a better formula: n(n+1)(n+2)/6
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Answer to:
What is a differentiable function?
The derivative of a function 'f' at a point 'a' is the limit:
lim x->a (f(x)-f(a))/(x-a)
If this limit exists then f is said to be differentiable at 'a'. If f is differentiable at every 'a' then 'f' is said to be differentiable.
In simple terms, it's differentiable if its derivative exists at every point.
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Answer to:
How do you convert mm into mm3
Multiply by mm^2
(an area).
| 1 person likes this
Answer to:
Name a prime number more than 20 but less than 50.
How to find ALL prime numbers between 20 and 50.
Write down all odd numbers between 20 and 50:
(those that are not divisble by two, the first prime):
21 23 25 27 29 31 33 35 37 39 41 43 45 47 49
Cross out those divisible by three (the second prime):
23 25 29 31 35 37 41 43 47 49
Cross out those divisible by five (the third prime):
23 29 31 37 41 43 47 49
Cross out those divisible by...
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Answer to:
If I have 2 segments tangent to a circle from the same exterior point and a third segment tangent to the circle and connect to the other 2 segments, how can I find the radius. ( I only know the mesurement of 1 of the 2 segments 15)
The two lines tangent to the circle will be the same length, because a line joining the exterior point to the center of the circle will be a line of symmetry.
But that's all I can tell from your question.
Label the points where the lines and circles cross, and tell me that there is a circle through points P Q R and S and a line though points ... and this line is tangent and so on,...
Answer to:
What is x3-3x2-9x+2 divided by x+2?
Dividing polynomials is a bit like dividing integers:
1234/12
is 1*10^3 + 2*10^2 + 3*10 + 4 / 1*10 + 2
which is a similar problem with 10 instead of x.
(x^3 - 3x^2 - 9x + 2) = something * (x+2)
Looking at the x^3 on the left and the x on the right,
the first term of something must be x^2
(x^3 - 3x^2 - 9x + 2) = (x^2 + something) * (x+2)
now the right side makes x^3 + 2x^2 + things
...
Answer to:
Wat iz da set 0f all REAL zer0s 0f da p0lyn0mial functi0n? f(x)=x3+3x2+4x+12
All the terms are positive, so if x is positive, f(x) cannot be zero.
If there is an integer x which makes f(x) zero then it must be negative, and a factor of the last term:12
so try -1 (no)
try -3 makes: -27 + 27 -12 + 12 which is zero.
So x = -3 is a zero.
So x + 3 is a factor.
You would now divide by x+3 and start again.
You can also use the 'grouping' method:
...
Answer to:
If the probablity that a men aged 60 will live to be 70 is o.65 what is the probablity that out of 10 men, now 60, at least will live to be 70?
There is a digit missing from your question, but this is the binomial distribution and the formula you use to work this out is:
P(exactly i men live to 70) = nCi p^i q^(n-i)
where n=10
nCi is the binomial coefficient
p is 0.65
and q is 1-0.65=0.35
Answer to:
A pair of fair dice is thrown.If the two numbers are different,find the probability that (i)the sum is six; (ii)a '1' appears.
Let the dice be colored red (R) and green (G)
then the possibilities are:
R1G2=3 R1G3=4 R1G4=5 R1G5=6 R1G6=7
R2G1=3 R2G3=5 R2G4=6 R2G5=7 R2G6=8
R3G1=4 R3G2=5 R3G4=7 R3G5=8 R3G6=9
R4G1=5 R4G2=6 R4G3=7 R4G5=9 R4G6=10
R5G1=6 R5G2=7 R5G3=8 R5G4=9 R5G611
R6G1=7 R6G2=8 R6G3=9 R6G4=10 R6G5=11
Thirty possibilities when the two numbers are different.
The sum is six in four of those cases. The...
Answer to:
I invented the basics of sexual reproduction, getting around from place to place, and how to use energy from the Sun. Who am I?
You must be some sort of plant.
Plants have sexual reproduction, get around by dispersing seeds and use photosynthesis to get energy from the Sun.
Am I right?
Answer to:
If by every action there is a reaction then by definition is this faster than light?
Classically when you say 'action' and 'reaction' this refers to the action of body A on body B and the action of body B on body A which happen at the same time because this is the definition of the conservation of momentum. A gains some momentum from B or vice versa.
There is no delay as that would break the Law of conservation of momentum.
In practice though body A acts...
Answer to:
CAN 5X^2 BA FACTORED?
Yes. If you don't know anything about x, then the most you can do is factor it into three factors: 5, x and x.
Answer to:
Could you please tell me what really happened , did Thomas Edison really create light bulbs, or steal the invention? I also hear that he did something to NIKOLA TESLA
Humphrey Davy invented the incandescent light in 1802.
Edison's version became a commercial success because he produced the entire system: electricity generation and transmission as well as lighting, not just because he had got a good material and a good vacuum in his bulb.
Answer to:
What is the heaviest element in the universe?
The heaviest element per cubic meter may be Osmium.
Answer to:
Is there a difference between frozen and solid? For example: at -39c is mercury frozen or is it a solid....or are they both the same state?
If the surface of a lake freezes, we say the lake is frozen even if it is still liquid further down.
So frozen means all or perhaps part of the liquid has become solid.
Answer to:
In a certain college,25% of the male students and 10% of the female students are studying mathematics.Girls constitute 60% of the student body.A student is chosen at random.Find the probability that the student is studying mathematics.
Let there be 100 students.
Then 60 are female and 40 male.
A quarter of the male students are studying math: 10.
A tenth of the female students are studying math: 6.
Total studying math = 16 = 16%
Probability that random student studying math = 0.16
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Answer to:
Can a ghost hurt or kill,a living human being? I am serious!
Even if it were true that ghosts don't exist, it is possible for someone who thinks they have seen a ghost to die of fright. (Heart Attack).
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Answer to:
Let z >= 2 find x > 0 such that x+x^-1=z. On the assignment, the > is directly above an equals sign, not a straight line. Is there anything to find? This seems true for all x > 0 help!
I think this is just asking you to solve the equation
x+x^-1 = z
for x.
So multiply by x:
x^2 + 1 = z x
x^2 - z x + 1 = 0
So x = (z +/- sqrt(z^2 - 4))/2
if z>=2, then z^2-4 is >= 0 but <z^2
so 0 <= sqrt(z^2 - 4) < z
and x will then be between 0 and 2z
Both solutions for x will suit the conditions.
Alternatively it may be asking you to find a particular x and z...
Answer to:
If (2/3)x = 6, then x = 4. Correct; we can prove this with the given information. Incorrect; we can not prove this with the given information.
If two thirds of x is 6 then x can only be 9, obviously.
Therefore there can be no proof that x = 4 given this information, only a disproof.
Answer to:
Do virus really take on geometric shapes?
The regular platonic solids occur in creatures called radiolarians http://en.wikipedia.org/wiki/Radiolarian
Other geometric solids appear in viruses, such as a stretched icosahedron in the T4 Bacteriophage:
http://en.wikipedia.org/wiki/Bacteriophage_T4
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Answer to:
Has anything EARTHMOVING, GROUNDBREAKING, PROFOUND, or new been learned from that Large Hadron Collider in Switzerland? What were they looking for and what would it have meant for the rest of humanity? What justifies 9 billion in expenditures?
This obsession with how much everything costs seems to be a particularly north american phenomenon.
Look at it this way. The transistor could not have been invented without the discoveries which were made with particle accelerators.
Without the transistor, it is very unlikely you'd be able to read what I just wrote.
The World Wide Web was invented at Cern, which runs the LHC.
...
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Answer to:
A hound was chasing a fox. whenever the hound took 4 leaps, the fox took 5. If 3 hound leaps cover the same distance as 4 fox leaps, the fox's head start was equal to 90 hound leaps, how many leaps did the hound need to catch the fox
3 hound leaps = 4 fox leaps.
This would be easier if this was a (lowest common) multiple of 12 somethings. Say 12 feet.
Then a hound leap is 4 feet.
A fox leap is 3 feet.
the fox's head start was 360 feet
The hound leaps 4 leaps = 16 feet
the fox leaps 5 leaps = 15 feet.
The hound has gained by a foot.
It's going to take 360 lots of this for the hound to catch up.
360 lots of...
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Answer to:
In an alloy of 150 pounds of zinc and copper, there are 100 pounds of copper. How much copper must be added so that the alloy may be 10% zinc?
You have 50lb of zinc.
And you want that to be 10%
The whole must be 500lb
There must be 450lb of copper.
But you already have 100lb of copper.
So you have to add some.
Answer to:
What are all four digit combinations of the numbers 2,2,6 and 8?
If the two 2s were different, there'd be 4*3*2*1 combinations.
But if we don't care about the order of the 2s then they could go either way round, so that's half as many = 12 combinations.
How to list them systematically:
The first digit will successively be 2,6,8
for the second digit pick each of the remaining choices in order of size.
for the third digit pick each of...
Answer to:
List the congruencies and proportions if Triangle ABC~Triangle QRS
Presumably '~' stands for 'is similar to'
Angle A = angle Q
Angle B = angle R
Angle C = angle S
and the ratios:
AB:QR = BC:RS = CA:SQ
AB:BC:CA = QR:RS:SQ
Answer to:
Using direct variation. Neglecting air resistance the distance an object falls from the rest varies directly with the square of the time of fall. If an object falls 21.5 feet in 1.4 seconds, how far will it fall in 4 seconds?
1.4 squared is 2 more or less.
4 squared is 16 which is 8 times as much.
so the object falls 8 times as far (direct variation)
I make that about 172 feet.
Doing it exactly you need to do 21.5 * (4/1.4)^2
Answer to:
Has a sun ever been discovered orbiting a planet?
It's a common misconception that planets orbit the Sun.
In fact, they both orbit the common center of gravity.
It's just that the Sun is so much heavier than the planet that the Sun has a much smaller orbit and from a distance, would only seem to wobble from side to side.
This wobble can be used to detect planets orbiting other stars.
Answer to:
Construct a Formula x= 1, 2, 4, 5, 7 and y= 7, 11, 19, 23, 31
You did say construct a formula rather than find a formula.
A way to construct a formula is to add five terms corresponding to each value of y:
Each value of y is multiplied by a polynomial which is zero at the other values of x but 1 at that value of x
This polynomial for y=19 in your example is:
(x-1)(x-2)(x-5)(x-7) / (4-1)(4-2)(4-5)(4-7)
clearly its zero if x is 1 2 5 or 7 but exactly 1...
Answer to:
If you define something mathematically as X <> Y, is it possible for X and Y be equal?
X<>Y normally means that X is not equal to Y.
It's a computer science convention rather than a math convention. The math convention is to write = with a / through it.
So unless you have some other meaning in mind for '<>' then X <> Y means that X and Y are NOT equal.
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Answer to:
Can this be simplified to solve for x: be^x/b - 4dce^x/c = 4c+b
**NOT HOMEWORK** Just can't work it out myself =)
Presumably you mean:
b e^(x/b) - 4 d c e^(x/c) = 4 c + b
put y = e^(x/b)
b y - 4 d c y^(b/c) = 4 c + b
if I pick b=5 and c=1 I get a quintic equation which cannot be solved in closed form.
So depending on the numbers, I don't think you can solve this, except approximately.
How did you arrive at that equation?
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Answer to:
If (2/3)x = 6, then x = 4. Correct; we can prove this with the given information. Incorrect; we can not prove this with the given information.
If two thirds of x is 6 then x is 9
Pretty obvious isn't it?
Therefore x=4 is not correct.
Therefore there can be no proof, only disproof.
EDIT: -1 points why?
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Answer to:
Ray OP is in the interior of angleXOY. What can be said about angleXOY in relation to angleXOP and anglePOY?
XOY = XOP + POY
XOY = XOP - POY
XOY + XOP = POY
Draw a diagram.
This will become easy.
I hope.
EDIT: Draw the diagram BEFORE rating my answer. No really. Draw it.
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Answer to:
Point P is the interior of angleXOY. Does the ray with end point O and containing point P lie completely in the interior of angleXOY? Yes; Ray OP is in the interior. No; Ray OP is on one ray of the angle. I can't tell
Apart from the point O itself, the ray OP lies in the interior if P does.
(assuming Euclids 5 postulates etc)
Answer to:
Ray OP is in the interior of angleXOY. What can be said about angleXOY in relation to angleXOP? OP + OY > OX angle XOP is 1/2 angle XOY angle XOY > angle XOP
What does Ray OP in the interior of angle XOY mean?
Let [ABC] denote that A B and C are distinct and lie on a line in that order.
Then I could say that OP is in the interior of XOY if there is a Q not equal to O with [XQY] and either [OPQ] or [OQP] or Q=P
Then angle XOP + angle POY = angle XOY and each angle is positive so angle XOY > angle XOP
Answer to:
How do u factor x cubed + 4x squared - x - 4?
If you're stuck, look for a value where the polynomial is zero. Graphing can help.
Noticing that the x^3+4x^2 is similar to the -x-4 part is the best way as Anonymous said but if you don't notice that -x-4 and x^3+4x^2 have a common factor which you can take out, then you can use the guess/graph method.
Try small integers for x to see if you can make the equation zero.
Cubic:...
Answer to:
If we multiply a 2*2 matrix with a 2*1 matrix, the product is a 2*1 matrix. true or false
True.
a A*B matrix multiplied by a B*C matrix makes a A*C matrix.
no other combinations are allowed.
In your example A=2,B=2,C=1
Answer to:
Solve for all three variables in the following equations using ONLY the substitution method; 2x + 3y - 4z = 8, x= 4y + 2z - y, and 12 = 6y + 2x + 7z. Show your steps.
Substitution method...
Solve one of the equations for one of the variables. I pick x in the library with the second equation.
So x = 4y + 2z -y.
Substitute for x in the other equations:
First equation:
2(4y + 2z - y) + 3y - 4z = 8
Third equation:
12 = 6y + 2(4y + 2z - y) + 7z
Now rinse and repeat on those two equations until you have the numerical value of one of the variables.
...
Answer to:
Find the x intercept for the graph for the equation x+y=9
an x intercept is the x co-ordinate where the graph intercepts the x axis.
The x axis has y=0 everywhere along it.
if y=0 and satisfies your equation, what is x?
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Answer to:
The graph of the following system yields parallel lines. x + 4y = 5 and -3x = 12y - 13. true or false
Suppose the lines are not parallel. Then they meet. There is an unique x and y which are on both lines.
So x+4y=5 and -3x = 12y-13 at the same time.
add three of the first equation to the second to eliminate x:
12y = 12y - 8
That's nonsense. A contradiction.
So the assumption that the lines are not parallel is wrong.
So the lines are parallel.
Method 2:
Write in the form y = mx +...
Answer to:
What is the ones (units) digit for 3 to the 8th power and how to get the answer?
3^8 is (3^2)^4 which is 9^4
9^4 is (9^2)^2 which is 81^2
81^2 is 80*80 + 80*1 + 1*80 + 1*1
= 6400 + 80 + 80 + 1
= 6561
OR you could note that the rest of the digits except the ones digit don't make a difference:
so
3^1 = 1*3
3^2 = 3*3 = 9,
3^3 = 9*3 = 27 = ???7
3^4 = ???7*3 = ???1
so multiply anything by four lots of 3 and the last digit is multiplied by 1
so 3^8 =...
Answer to:
What is the pattern to these numbers: 1,2,3,6,18, _, _, _?
There's not quite enough info to be sure.
OEIS gives four sequences:
http://www.research.att.com/~njas/sequences/?q=1%2C2%2C3%2C6%2C18&language=english
I wonder if the 1 at the beginning is a mistake, because without that, each number is the product of the previous two.
Answer to:
Is it true, without exception, that if P, Q, R are points contained by plane X and also by plane Y, then X is the same as Y?
Yes; they must be on the same plane.
No; the points may be on a line at the intersection of the 2 planes.
In three dimensions, P Q R defines a unique plane only if the three points are not colinear.
If the three points lie in a line, then any plane through that line will share those three points and the 'no' part of your question applies.
But if P Q R are all the same, then any plane through P will do, and the question doesn't account for that.
Answer to:
Plane X and plane Y each contain the point A. Is there a line containing A which is common to the lanes? Yes No
In three dimensions, yes.
In higher dimensions, if the planes have two degrees of freedom, then no, two planes can intersect in 1 point only. Example, in four dimensions if one plane is the XY plane so that X=0 and Y=0 and the other is the ZW plane so that Z=0 W=0, the only point in common is the origin.
Answer to:
If Y is greater than Z, A is greater than X, and X is equal to Z, is Y greater than A?
Let Z,X be 0
Let A be 1
Then all the conditions are satisfied as long as Y is
bigger than 0.
But I can pick Y to be the same, less than or greater than A as I like as long as Y is greater than Z.
Answer to:
How do I do these problems: IF m = 2 and y = 2, then m = y
Equals may be substituted for equals.
Assumption: m=2 and y=2
2=2 obviously.
m=2 (I substituted m for 2 as we have m=2)
m=y (I substituted y for 2 as y=2)
Therefore
if m=2 and y=2 then m=y
[The last step is called implication introduction in a natural logic course]
Answer to:
How many combinations are there in 0 threw 9
Well the are ten digits if you meant "how many digits are there in 0 thru 9".
If you're allowed more than one digit, you can make "aleph-0" numbers...
Answer to:
Is this correct: If AB = XY and PQ = XY, then AB = PY.
AB means the length of the line joining points A and B.
In your question we have six points:
AB
is the same length as
XY
is the same length as
PQ
but just as I've written it, there could be a huge gap betwen the XY points and the PQ points so PY could be anything. Unless you have a diagram...
Answer to:
Find a dissection of a rectangular hexagon into 8 congruent quadrilaterals?
Take four hexagons. Divide them in half between two vertices to make 8 congruent quadrilaterals.
Fit them together again to make one big hexagon.
Hint: put two of them together to make a small hexagon and put the rest around the outside.
Answer to:
A man leaves his home and walks 3 miles south, then 3 miles west, shoots a bear, walks 3 miles north to home, what color is the bear?
The bear is black.
Here's how I know:
There are no bears in the Antarctic.
A man who lived on the north pole would end up back at the north pole.
Bears who live in the Arctic are polar bears.
Polar bears are black.
(Yes yes, I know they LOOK white, but that's just the fur! Believe it or don't they are black underneath! )
Interesting addition. Forget the...
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Answer to:
What is the distance on a number line between two points with coordinates -56 and 19?
Walk 56 miles to get to the zero. Walk 19 more miles to get to the 19.
That's 56+19 miles in all.
Answer to:
10: If B, C are points on a line segment AD such that AB = CD and the points are in the order A, B, C, D, then AC = BD. Correct; we can prove this with the given information. Incorrect; we can not prove this with the given information. 11: In Exercise 10,
If we are given the order, then we do know that
AB+BC = AC
and BC+CD = BD
Subtract:
AB-CD = AC-BD
if AB=CD then the left side is zero.
so the right side is zero
so AC=BD
Are you supposed to prove this from axioms? That would be much harder.
Answer to:
If Angle ABC = Angle PQR, and if a ray BH divides Angle ABC into equal parts and a ray QK divides Angle PQR into equal parts, then Angle ABH = Angle PQK. Correct; we can prove this with the given information. Incorrect; we can not prove this with the giv
It depends what 'divides an angle into equal parts means'
A ray could divide 30 degrees into two 15 degree angles.
But is the ray allowed to go the other way and divide 330 into two 165 degree angles instead?
Answer to:
X, Y are points on the line segment AB such that AX = XY = YB. P, Q are points on the line segment LM such that LP = PQ = QM. If AB = LM, then AX = LP. Correct; we can prove this with the given information. Incorrect; we can not prove this with the given
It seems obvious.
But you can't prove it.
A counter example is when:
X=B
Y=A
So that AX=XY=YB = the length of AB
but take LP = PQ = QM are each one third of LM=AB.
Answer to:
If AB and PQ are equal line segments, and if AB = 1/2 XY, and PQ = 1/2 LM, then LM = XY. Correct; we can prove this with the given information. Incorrect; we can not prove this with the given information.
Let AB = x
Then PQ = x
XY = 2x
LM = 2x
So XY=LM
Answer to:
Are there hypercomplex numbers, A,B,C, such that:
1. A+B=B+A
2. A*B=B*A
3. A(B+C)=A*B=A*C
4. A-B=A+(-B)
5. A/B=A*B^(-1) iff B is not zero nor a zero divisor?
That is to say, are there hypercomplex fields?
Your stated properties are true of real numbers and rational numbers as well as complex numbers.
There are many kinds of hypercomplex number many of which are not commutative. See http://en.wikipedia.org/wiki/Hypercomplex_number
But if you just want a field which is "bigger" than the complex numbers but satisfies your properties, then take the field Frac C[x] of rational...
Answer to:
How do you know the derivative of x^2 is 2x? In other words, How do you find a derivative?
Actually this is more complex than it seems.
In principle, you find the slope of the graph at a point x on the y=x^2 graph.
But to define this rigorously took many years.
There are two alternative definitions, one which uses a limits and is the established one, and one which uses infinitesimals (which I don't fully understand).
The limit definition of the derivative of a...
Answer to:
I am trying to gain a basic understanding of MS Excel's "Regression" output data. I am looking for someone who can give me a layman's understanding of "R Square", "Multiple R", and other data elements in the analysis. Please help?
I can tell you about 'r' the coefficient of regression. (RSQ is probably the square of that).
Suppose your data values are x[i] and y[i]
Suppose you denote the sum over i of x[i]*y[i] as Sxy
Then if the x[i] and y[i] have mean of zero, the line of best fit is given by
y_fit = (Sxy/Sxx) x
(you can arrange for the x[i] and y[i] to have a mean of zero by subtracting the mean...
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Answer to:
What is the chance of a car you used to own running up the back of you
Suppose there are N car drivers in the general area where you drive and you handed over J of your previous cars to people in this area and have had K car accidents.
The chance is then approximately J*K/N that one of these car accidents involves a car you used to own.
I can be fairly confident that N is less than a million, so the chance is less than 1 in a million.
Now an interesting...
Answer to:
A candy company produces chocolate bars,in which 35% of the bars are almond. a sample of 20 bars is taken. what is the probability of exactly 10 of the bars having almonds?
Binomial distribution
P(i bars with almonds) = nCi p^i q^(n-i)
Hints:
P(x) means 'probability of x'
nCi is the binomial coefficient.
For your case 20C10 is 184756
p is the probability of almonds in a single bar (0.35)
q is 1-p
Answer to:
Find the value of: (log2(cos(5pi/3))^2)^3 + (log3(tan(-pi/6))^2)^3.
Please show steps.
pi radians in half a circle.
5pi/3 = 300 degrees.
cos 300 = cos 60 = 0.5
squared is 0.25
log2'd is -2
cubed is -8
-pi/6 = -30 degrees.
tan (-30 degrees) = - tan (30 degrees) = -sqrt(3)/3
squared = 1/3
log3d = -1
cubed = -1
added = -9
If you're not sure how to find cos 60 or tan 30, draw an equilateral triangle of side 2, and bisect it into two right triangles and...
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Answer to:
If AB = 5y - 4, BD = 7y + 3 and AD = 20y - 9, find the value of y.
Without a diagram, all we can say is that ABD is a triangle.
Some values for y are not permissable.
y is greater than 4/5 from the first equation.
AD is the longest side, but it may not be greater than AB+BD = 12y-1
so 20y-9 <= 12y+1
8y <= 10
y <= 5/4
so y is somewhere between 4/5 and 5/4
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Answer to:
A friend states that he has two children and that at least one of them is a girl. What are the odds that the friend has a boy and a girl as children? More importantly, why is there so much controversy about the answer?
Here are four roughly equally likely outcomes for two children:
1) Eldest is a boy, youngest is a boy.
2) Eldest is a boy, youngest is a girl.
3) Eldest is a girl, youngest is a boy.
4) Eldest is a girl, youngest is a girl.
But we know that #1 didn't happen in your friend's case.
Therefore we have three equally likely events: #2, #3 and #4.
In two of those cases, the friend...
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Answer to:
How many SECONDS are in ONE DAY?
There were 86401 in Dec 31, 2008
They added a leap second because the Earth's rotation is generally slowing down.
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Answer to:
What does the proof that 1+1=2 look like?
This page gives a proof of 2+2=4 in a similar way to Whitehead and Russell's proof of 1+1=2
http://us.metamath.org/mpegif/2p2e4.html
The complete proof makes use of 2,452 subtheorems taking a total of 25,933 proof steps.
The subtheorems are similar to those in Principia Mathematica.
EDIT: Metamath also has the 1+1=2 proof:
http://us.metamath.org/mpegif/pm54.43.html
and
...
Answer to:
Shuffle 2 packs of cards, deal them all between 2 people, who then play Snap, looking for a match for a named card, say the 2 aces of clubs. What is the probability of a match coming up in any one game?
I interpret the question to mean this:
shuffle the 104 cards and order them.
The odd placed cards go to one player and the even placed cards to the other player.
The combinations in which NO match comes up, are when
card one is different from card two
AND
card three is different from card four
AND
card five is different from card six
and so on.
I can estimate this probability
The...
Answer to:
In Trigonometry, What is the Law of Sines and the Law of Cosines?
Let ABC be a triangle with sides a,b,c and angles opposite each of those sides, A,B,C.
Then the Law of Sines is:
a / sin(A) = b / sin(B) = c / sin(C) = 2r
where r is the radius of the circumcircle.
You can use this to find a missing quantity if you have 2 adjacent sides and an angle, or two adjancent angles and a side.
The Law of Cosines:
a^2 = b^2 + c^2 - 2bc cos A
A bit...
Answer to:
Happy New Year 2009, everyone! I am curious: is 2009 a prime number? If not, what is it a multiple of?
How to find factor of a number N.
First, a quick 2,3,5 test:
If the number is even, it has a factor of 2.
If the "digital root" of the number is divisible by 3, it has a factor of 3. The digital root is what you get when you repeatedly add up the digts until you are left with just one digit.
If the number ends in 5, it has a factor of 5.
Plan to divide prime numbers...
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Answer to:
How can we prove that there IS NOT a black hole, or a planet on the "other" side of the Sun?
Hi Chris, I'm sure you already know this, but the point opposite to the Earth behind the Sun is an unstable equilibrium. It is called the L3 "Lagrange point". A body will orbit nicely there behind the Sun for a short while, but even a microscopic tug on the planet from other bodies such as Mars will cause it to 'fall' out of the equilibrium towards the L4 and L5 points,...
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Answer to:
How do you figure squareroot in long math?
Group the digits into pairs, starting at the decimal point and going each way. The first group will have one or two digits.
Take the first group and pick the digit whose square is less than or equal to the first group. This is the first digit of the answer.
Subtract first-digit-squared from the first group and bring down the next two digits.
Every subsequent step is found like this:
...
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Answer to:
What function(s) f(x) have its inverse equal its derivative? like f'(x) = f^-1(x)?
Try f(x) = (x/a)^n
Inverse function = a x^(1/n)
Derivative = n/a (x/a)^(n-1)
if these are equal then n-1 = 1/n.
So n^2 - n -1 = 0
So n = phi, the golden ratio 1.618, or phi - 1
a^2 = phi/(phi)^(phi-1)
a = about +/-1.096
So one function is near to (0.912 x)^(1.618)
The other solution phi-1 will give other answers.
There may be other answers.
I'll have to come back to...
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Answer to:
Why does orange juice taste so bad after I brush my teeth?
Most western toothpaste now contains detergent.
The detergent is there to help clean the teeth but also to froth up and make the foamy toothpaste we've come to expect. It's not really necessary - it's just a marketing thing.
The detergent strongly interferes with our sense of taste, making sweet things taste bitter.
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Answer to:
If abc=1 , show that (1+a+1/b)-1+(1+b+1/c)-1+(1+c+1/a)-1=1
I've seen a question like this:
If a,b,c are positive and abc=1, show that (a-1+1/b)(b-a+1/c)(c-a+1/a)<=1
I've seen an answer like this:
Take the first two brackets:
(a-1+1/b)(b-1+1/c)
= ab - a + a/c - b + 1 - 1/c + 1 - 1/b + 1/bc
= a/c - b + 2 - 1/b (cause 1/bc is a and 1/c is ab)
= a/c -(1-b)^2/b
That last term is positive, unless b=1 when it is zero.
...
Answer to:
The ages are 37,39,14 b. How many years older was the person older than you when you were born? c. Write an equation that models how old in years each of you will be, when your ages add up to 150 years old. For example, if the eldest person was one year o
Are you 14?
When you were born the other two ages would be 23 and 25.
I subtracted 14 from each age.
n years after you were born the ages will be
23+n, 25+n and n.
if 23+n + 25+n + n = 150
then 48+3n = 150
3n = 102
n = 34. You will be 34 years old.
and the other two ages will be 57 and 59.
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Answer to:
What is the percent for the number 2?
17.6%
According to Benford.
But I think the percentage you're after relates to the rest of the question.
EDIT: Whoever liked -2 as a points value for this answer, try looking up Benford's law and stop downrating without owning up.
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Answer to:
In a normal distribution 31% of the items are under 45 and 8% are over 64. Find the mean and S.D. of the distribution.
How to do this:
Look on a chart to find how many sigmas below the mean 31% corresponds to. That is, what value on the standard normal distribution has only 31% of the area of the graph to the left of it.
If you haven't been given a chart or table, you can use a table like this one: http://www.isixsigma.com/library/content/zdistribution.asp
This particular table gives the area...
Answer to:
If the sum of first n terms of two arithmetic progression are in the ratio (7n + 1) : (4n + 27), find the ratio of their 11th terms.
The sum of a arithmetic sequence:
a, a+d, a+2d, a+3d, ..., a+(n-1)d
is na + n(n-1)d/2
(use the rule "average of first and last multiplied by number of entries")
If we were to divide these, one factor of n would disappear and wed' be left with a + (n-1)d/2
or (d/2) n + (a-(d/2))
But this is just the same form as the ratios in the question. (something times n + something)
...
Answer to:
Is zero times infinity undefined? Or is it just zero?
It depends.
4-x tends to zero as x tends towards 4.
1/(4-x) tends to infinity as x tends towards 4.
Multiply them, you get 1, whatever x is, even if you let it be 4.
8-2x tends to zero as x tends towards 4.
1/(4-x) tends to infinity as x tends towards 4.
Multiply these, you get 2, whatever x is, even if you let it be 4.
4-x tends to zero as x tends towards 4.
1/(4-x)^2 tends to...
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Answer to:
Find the nearest coin, flip it. Heads or tails? I want to see if it's really equal.
I had several coins in my pocket so I just threw them all up and got:
head tail head head tail head tail tail head head tail head head tail tail head tail head head.
The Law of large numbers says if you keep doing it, the proportion of heads will get closer and closer to a half.
But you have to actually do that division: number of heads divided by total number of coins.
Because, suppose...
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Answer to:
15.5% of a X is 3,690. What is the X? What is the formula to arrive at X?
"of" is "multiplied by"
and 15.5% is 15.5/100 as a fraction.
so
(15.5/100) multiplied by X = 3690
divide both sides by 15.5/100
X = 3690 divided by (15.5/100)
Answer to:
OK Math People. Pi (3.14.....) is a real number that has no specific sequence ,which is infinite, after the point (3.14159265.....), does that mean that any combination of numbers I could come up with has to exist somewhere in Pi? -does that make sense?-
Pi is believed to be normally distributed, which means any finite combination of digits you could come up with has to exist somewhere in Pi.
This use of the word 'normal' nearby to a word related to 'distribution' has no direct connection to the 'normal distribution'.
It doesn't follow that just because there is no obvious sequence and that the sequence...
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Answer to:
How many digits of Pi can you recite? And- How is Pi calculated?
First part: http://www.answerbag.com/a_view/1086465
Second part: http://www.answerbag.com/a_view/623465
Answer to:
Hello, my question is a bit big, so I will ask the question in an answer reply.
Thank you.
Well I say, move on.
These friends are not helping to make your life fun, there are more people out there.
Be cool. Be confident.
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Answer to:
What is the mast popular expression on earth?
Okay
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Answer to:
Sorry not billion. My son asked what is one million times three hundred million
300 trillion.
because a million times a million
= a thousand times a thousand times a million
= a thousand times a billion
= a trillion.
This assumes your country uses "short scale" numbers, like the USA; and the UK now do also.
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Answer to:
What is -65 c in f?
degrees C are bigger than degrees F.
There are only 5 degress C to 9 degrees F.
(water: 0 to 100 degress C, but 32 to 212 F = 180 F)
-40 is the same on both scales.
-64C is 24 degrees C below the magic -40
That's 24/5 lots of 5 degrees C below -40
= 24/5 lots of 9 degrees F below -40
= 24*9/5 degrees F below -40
= -40 - (24*9/5) degrees F
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Answer to:
What happens to the margin of error as you increase the confidence level?
confidence good.
error bad.
confidence increased.
error decreased.
Answer to:
Explain the relation between fourier series, and the fourier transform.
Thanks!
An example of a fourier series:-
a[0]/2 + sum n=1..inf, (a[n] cos nx + b[n] sin nx)
on the interval x in [-pi,pi]
where a[n] = (1/pi) integral x in [-pi,pi] f(x) cos nx dx
b[n] = (1/pi) integral x in [-pi,pi] f(x) sin nx dx
cos nx is the real part of e^inx
and sin nx is the imaginary part of e^inx
so a[n] = Re (1/pi) integral x in [-pi,pi] f(x) e^inx dx
b[n] = Im (1/pi) integral...
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Answer to:
Can the cube of a negative number be a positive number?
Let -x be any negative number
(So x is a positive number)
The cube of -x is (-x)*(-x)*(-x) = -x^3
and x is positive, so x^3 is positive so -x^3 is negative.
So the cube of a negative number is always negative.
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Answer to:
Wha is the mean of (x + 4) and (x + 6)?
'mean' means 'average'.
What's the average of (x+4) and (x+6)?
to find the average, you add up all the data and divide by the number of items.
Add up all the data: (x+4)+(x+6) = 2x+10
divide by the number of items, which is two: (2x+10)/2
Answer to:
What word can be made out of the following letters using all of these letters? o a t i s g o l
There are a couple of words that can be made which use all of those letters:
Algologist - someone who studies algae.
Glassologist - someone who is an expert in defining terms.
Of course, I had to use some of the letters more than once.
Answer to:
In which direction does the function f(x)=-4(x+2)^2-3 open
Downwards. You could just remember that y=x^2 is upwards,
therefore y=x^2-3 is still upwards (but moved downwards a bit)
and y=(x+2)^2-3 is still upwards (but moved leftwards a bit
and y=4(x+2)^2-3 is still upwards (but expanded a bit vertically)
but y=-4(x+2)^2-3 is ... upside down.
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Answer to:
Help what is a heavy common household object? (not a tv/computer, -makes a noise/produces light/has buttons/fragile.)
Microwave.
Not sure about the fragile.
Answer to:
In right triangle ABC, altitude CD is drawn to hypotenuse AB. If AD=5 and DB=24 what is the length of CD?
This only makes sense if C is the right angle.
Pythagoras: (CD)^2 + (AD)^2 = (AC)^2
Pythagoras: (DB)^2 + (CD)^2 = (BC)^2
Pythagoras: (AC)^2 + (BC)^2 = (AB)^2
(CD)^2 + (AD)^2 + (DB)^2 + (CD)^2 = (AB)^2
2 (CD)^2 + 5^2 + 24^2 = 29^2
(CD)^2 = 120
CD = sqrt(120)
about 11
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Answer to:
How do I factor 15x2 + 7x – 2?
Using the middle term method.
See http://www.answerbag.com/q_view/1126040
Answer to:
What I am asking is if leap year had never been started then what would todays date really be? You must stop to think if leap year had never been started todays date would be different then what it is now alot of days would be taken away
It's not really possible to answer that because we have always taken into account that the number of days in a year is a bit over 365 since prehistoric times.
The leap year as we know it today was introduced in 45BC
(before that an extra month was used every now and again instead, following the lunar cycle)
If for some reason, Julius Ceasar had forgotten to account for the extra...
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Answer to:
A satellite encircles Mars at a distance above its surface equal to 3 times the radius of Mars. The acceleration of gravity of the satellite, as compared to the acceleration of gravity on the surface of Mars, is
A)Zero
B)the same
C)1/3
D)1/16
The acceleration of gravity is given by GM/r^2
where G is the gravitational constant
M is the mass of the object (Mars)
and r is the distance from the center of the planet.
Suppose R is the radius of Mars.
You started with an acceleration GM/R^2
You ended with an acceleration GM/(3R+R)^2
because if it's 3 R from the surface, it's 3R+R from the center.
GM/(3R+R)^2 = GM/(16 R^2)...
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Answer to:
What is located at 41degree's North and 13 degree's east?
An island called Zannone off the coast of Italy, between Rome and Naples.
http://en.wikipedia.org/wiki/Zannone
http://maps.google.com/maps?f=q&hl=en&geocode=&q=41+N+13+E&ie=UTF8&ll=41.141433,13.002319&spn=1.720908,3.312378&z=8&iwloc=addr
P.S. There's no apostrophe needed in "degrees".
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Answer to:
A 3ft wide door is hinged to a wall. Find a formula for x, the angle the door makes with the wall, in terms of d, the door latch's distance from the wall. Can you help?
You have a right triangle.
The line joining latch to wall hits the wall at right angles.
The hypotenuse is 3ft, the line to the wall is opposite the angle you want and is d feet long.
SOHCAHTOA says if you have opposite and hypotenuse, you can make the Sine of an angle.
sin angle = d/3
angle = arcsin d/3
Answer to:
How do you solve for sinx+0.5=0 over the interval -pi is less than or equal to x which is less than or equal to pi?
sin is an "odd" function.
This means that sin -x = -sin x
(the graph is symmetric when you rotate it 180 degrees around the origin)
so if sin x+ 0.5 = 0
sin x = -0.5
sin (-x) = 0.5
What angle has a sin of 1/2
sin is Opposite / Hypotenuse.
If the Opposite is 1 and the Hypotenuse is 2 in a right triangle, then the Adjacent must be sqrt(2^2-1^2) by Pythagoras = sqrt(3)
Put two...
Answer to:
Is a photon considered one dimensional?
In QED, the established theory of light, photons are treated as ZERO dimensional: they have position but no size.
In some newer theories particles can have many dimensions as many as ten or more.
Answer to:
Can the existence of gravitons ever be proved? How?
Gravitons uniquely for known particles have spin 2.
A graviton that was generated in an interaction between particles in a particle accelerator would leave a distinctive signature.
Unfortunately gravitons interact so weakly that there is no practical way we could detect them this way.
We can only reason about them indirectly, just as Einstein showed that photons must exist before...
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Answer to:
Find the sum of first n terms of the series
3 × 8 + 6 ×11 + 9 × 14 + ....
I don't know how to do these. I'll see what I can come up with.
You have for each term m: (3*m) * (3*m+5)
So each term comes to 9 m^2 + 15 m
This is quadratic.
When you find the sum you're going to get a cubic equation.
a n^3 + b n^2 + c n + d
before you added on the nth term, the sum must have been:
a (n-1)^3 + b(n-1)^2 + c (n-1) + d
Find the difference:
3 a n^2 -...
Answer to:
How do you calculate the integral (squiggly s thing) tan^5(x)dx?
tan^5 (x)
sec^2 is 1 + tan^2
tan^2 is sec^2 - 1
So you have ((sec^2 x) - 1)) ((sec^2 x) - 1) (tan x) dx
put u = cos x
then du/dx = - sin x
and so - du/u = (tan x) dx
So now I have a new integral by u of
- ((1/u)^2 - 1) ((1/u)^2 - 1) du / u
multiplying that out:
- (1/u^5 - 2/u^3 + 1/u) du
which integrates to:
(1/4)/u^4 - 1/u^2 - ln u
= (1/4) sec^4 x - sec^2 x - ln |cos...
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Answer to:
The cost of operating a testing device for n minutes is given by C(n) = 1.4n² - 35n + 270 find the number of minutes the device had to be operated to minimize the cost? what is the minimum cost? %0
Complete the square:
C(n) = 1.4n^2 - 35 n + 270
C(n) = 1.4 (n^2 - 25 n + (270/1.4) )
C(n) = 1.4 ((n - 12.5)^2 - 12.5^2 + (270/1.4))
C(n) = 1.4 (n - 12.5)^2 + 270 - 12.5^2*1.4
C(n) = 1.4 (n - 12.5)^2 + 270 - 12.5^2*1.4
The first term is always greater than or equal to zero and has a minimum value of 0 when n=12.5
The rest gives the minimum value of C(n)
Test: Put n = 12.5+e where e...
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Answer to:
Here's the final number question (until 9 December '09) to replace the rejected question of 2 days ago. What springs to mind when I mention the number seventy seven?
Only seven elevens.
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Answer to:
What is the area of a polygon on the geoboard with 5 pinbs on the inside and 10 pins on the perimeter? A)8 B)13 C)25) D)9 E)27
That depends on the coordinates of the pins.
To work it out, find the sum:
of the values x1y2 - x2y1 for each side of the polygon.
Answer to:
Working together, Dave and Buster can mow the lawn in 12 minutes. Buster can mow the lawn by himself in 10 minutes less time than it takes Dave to mow the lawn by himself. How long does it take Dave to mow the lawn by himself?
Assume that D and B's rates add up.
D+B mow at 5 lawns per hour.
Don't know D's rate or B's rate in lawns per hour.
But given one lawn, D will mow it in 1/D hours
and B will mow it in 1/B hours.
and (1/B) is 10 minutes or (1/6) hours less than (1/D)
So
(1/B) = (1/D) - (1/6)
eliminate the fractions:
6D = 6B - BD
B+D = 5
B = 5-D
So
6D = 6(5-D) -...
Answer to:
What is the square root of 9x^6 / 64y^3?
9 is 3^2
64 is 8^2
so 3^2 x^6 / 8^2 y^3
halve all the powers:
3 x^3 / 8 y^(3/2)
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Answer to:
A horizontal curve on a bobsled run is banked at a 45 degree angle. When a bobsled rounds this curve at the curve's safe speed (no friction needed to stay on the run), what is its centripetal acceleration?
A) 1 g
B) 2 g
C) .5 g
D) None of the above
Consider the ground force F pushing up on the bobsled.
This is at a 45 degree angle to the vertical.
F cos 45 must match the bobsled's weight = m g
so F = m g / cos 45
But there is a left over horizontal component of
F cos 45 which acts to accelerate the bobseld around the curve.
F cos 45 = force of m g
So the centripetal acceleration = g
Answer to:
What is 51 2/7 - 18 5/6 in simplest form? (easy math problem)
Find a new denominator which is divisible by six and seven.
Answer: 42.
My method just converts everything into 42nds.
So 51*42 + 2*(42/7) - 18*42 - 5*(42/6)
=51*42 + 2*6 - 18*42 - 5*7
=2142 + 12 - 756 - 35
=1363 fortyseconds.
1363/42 = 32 and a bit.
32 is 32*42 fortyseconds = 1344
so 1369 fortyseconds is 32 and 19 fortyseconds
=32 19/42
Answer to:
What is the decimal equivalent of 2 and 2/5? (2/5 = 2 fiths)
Hint:
2 fifths
=
4 tenths
=
0.4
Alternatively:
2/5 of 10 is 20/5 = 4
so 2/5 is a tenth of that = 0.4
2 and 2/5 is a bit more.
Answer to:
A curve of radius 90 m is banked at 35 degrees. Suppose that an ice storm hits, and the curve is effectively frictionless. What is the safe speed with which to take the curve without either sliding up or down? A) 9.4 m/s B) 25 m/s C) 7.8x10^2 m/s D) Cant
The acceleration in a circle is v^2/r
EDIT: I messed this up.
A body travelling in a circle without falling is experiencing a centripetal acceleration of v^2/r
This centripetal acceleration must be due to the force left over from the ground pushing up on the vehicle after the force required to stop the car falling down is subtracted.
The ground force F is directed at 35 degrees to the...
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Answer to:
Find the equation of the circle that passes through the origin and has its center at (-1,-9). I have a few of these to do so please explain this to me! Thanks!!
If it passed through the origin its equation would be
x^2 + y^2 = r^2
But it doesn't. But moving the origin so that u=0 and v=0 is at the center of the circle would get:
u^2 + v^2 = r^2
u is zero when x is -1, so u must be x+1
v is zero when y is -9, so v must be y+9
(x+1)^2 + (y+9)^2 = r^2
x^2 + 2x + 1 + y^2 + 18 y + 81 = r^2
x^2 + y^2 + 2x + 18 y + (82 - r^2) = 0
Answer to:
If p varies inversely as q and q = 36 when p = 15, find p when q = 24.
if p varies inversely as q, then pq is constant.
We're told that q=36 goes with p=15 so the constant is 540.
if 24p = 540
then p = 22.5
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Answer to:
What is the difference between a hyperbola and a parabola?
Eccentricity?
A circle has eccentricity 0
An ellipse has eccentricity between 0 and 1
A parabola has eccentricity 1
A hyperbola has eccentricity greater than 1
From a planet-and-star type situation,
e=0: circular orbit
e between 0 and 1: elliptical orbit
e=1: planet passes and escapes star but only just getting ever slower and slower.
e greater than 1: planet whizzes past star,...
Answer to:
Evaluate the rational expression for x = -1 and x = 2. 4/x
That would be:
4/-1
and
4/2
(suitably simplified)
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Answer to:
Find the equation of the line that is tangent to the circle x^2+y^2-6x+3y-80=0 at the point (10,5). I think the answer is 13x-14y=-60. Any ideas?
The tangent must go through the point, so
13x-14y=-60 must work at 10,5
130-70y=+60 so your line cannot be right.
Here's a sneaky way to do it:
Suppose x and y vary somehow with t.
Find the derivative of the circle equation with respect to t
2 x (dx/dt) + 2 y (dy/dt) - 6 (dx/dt) + 3(dy/dt) = 0
substitute in given values for x and y:
20 (dx/dt) + 10 (dy/dt) - 6 (dx/dt) + 3 (dy/dt)...
Answer to:
Solve for X: log 4 +2 logx=log100
Rules you need:
x log y = log y^x
log x + log y = log xy
So using those rules:
log 4 + 2 log x = log 100
log 4 + log x^2 = log 100
log 4 x^2 = log 100
4 x^2 = 100
and now it's easy.
(but beware: there are two possible answers for x).
Answer to:
A four-digit number is formed from the digits 1,2,3,4,5,6, and 7. no digit may be repeated. how many odd numbers can be formed in this way?
Choose four numbers from 1,2,3,4,5,6,7
The formula for the number of ways of doing that is:
7C4 = (7*6*5*4)/(4*3*2*1) = 35
Now arrange the four numbers in any order.
There are 4*3*2*1 ways of doing that
That's 35*12 = 840 numbers using numbers from 1-7 with no repeating digit.
(1/7) of those will end with 1 = 120 of them.
(1/7) of them will end in 2
etc.
So 4*120 of them...
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Answer to:
Harry's rent a car offers two plans. the first plan costs $111 for 6 days with unlimited mileage. The second plan costs $11.95 a day plus $.15 a mile. When is the second plan the better buy?
I assume the first plan is $111 PER 6 days or incomplete fraction of 6 days.
First I assume you want the car for 6 days exactly
That will cost you $111 with the first plan
and $71.70 + $.15 a mile for the second plan.
The second plan is cheaper unless you do more than
(111-71.70)/(0.15) = 262 miles.
If you want the car for a multiple of 6 days, you have to stick to less than a total of...
Answer to:
The pine car rental plan is $18.95 a day plus 16 cents a mile. The cone car rental plan is 15.95 a day plus $.19 a mile. How many miles would you have to drive for the pine plan to cost less than the cone plan?
In cents:
pine car = 1895 + 16n where n is the number of miles.
cone car = 1595 + 19n where n is the number of miles.
subtract:
extra cost of pine car over cone car = 300 - 3n cents.
when n = 100 miles, the cars will cost the same.
If n is larger than this, the pine car wins.
So 101 miles. (assuming the plan works on complete miles)
Answer to:
A resteraunt offered pizza with 3 types of crust and 7 types of toppings. How many different types of pizza's could be offered?
A pizza can have only one type of crust at a time.
But it can have any number of toppings up to 7.
3 types of pizza with no toppings.
double that and put anchovies on half of them.
That's six kinds.
double that and put pepperoni on half of them.
That's 12 kinds.
double that and put sausage on half of them.
That's 24 kinds.
double that and put chicken on half of them.
...
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Answer to:
What is the tangent of a 60 degree angle?
SOHCAHTOA says Tangent is Opposite side over Adjacent side in a right triangle.
Draw an equilateral triangle of side 2. Each angle is 60degrees.
Cut it in half.
The halved base is 1 unit long.
The newly drawn height of the triangle is found by pythagoras to be sqrt(2^2-1^2) = sqrt(3)
The opposite side to the 60 degree angle is sqrt(3)
The adjacent side is 1
The tangent is sqrt(3)/1
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Answer to:
Traveling east at 60m/s. Behind it there is a car traveling along the same direction at 34.3 m/s. The ambulance driver hers his siren at a frequency of 934 Hz. The speed of sound is 343 m/s. At what frequency does the driver of the car hear answer Hz
It sounds from your question that the car behind is travelling the same speed as the ambulance.
That would make the answer 934 Hz.
Answer to:
What are the following three numbers in this sequence and why 2,6,18,27,....
This is my first attempt:
2
6= 3*2
18= 3*6
27 = 3*18 divided by two.
81 = 3*27
243 = 3*81
364.5 = 3*243 divided by two.
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Answer to:
OF THE EMPLOYEES WHO WORK AT STALLING PRINTING,90% ATTENDED THE SAFETY PROCEDURESMEETING .IF 63 EMPLOYEES ATTENDED THE MEETING, HOW MANY EMPLOYEES WORK AT STALLING PRINTING?
90% employees = 63
divide by 9:
10% employees = 7
multiply by 10:
100% employees = 70
total employees = 70
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Answer to:
Solve 27^(x+1)=9
take logs base 3:
(x+1) 3 = 2
because a^b -> b log a, and log3 3^3 = 3 and log3 3^2 = 2
3x + 3 = 2
3x = -1
x = (-1/3)
check: x+1 = 2/3 which as a power means square and cube root(in either order)
cube root 27 = 3, square 3 = 9. It works.
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Answer to:
Do you notice that there is allot of math Q's on here, Do you think that we are helping them with there homework?
Well this question is now in the "math homework" category. This is a clue.
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Answer to:
How do i figure out the next number in this sequence: 1663, 1527, 1126, 1096? I can't find a pattern.
The answer is 1746.
It is nothing to do with factoring. In fact it is bizarre that you have this question.
The question is from "Lenny Conundrum" from neopets.com
Have a look under the heading 2008 on this page: http://www.neopets.com/~loveywovey#08
Now add up the number of NP for each group of three days:
1st 324
2nd 945
3rd 394 1663
4th 953
5th 279
6th 295...
Answer to:
Whats the most important instrument on the Cassini-Huygens spacecraft? Why?
The most important instrument is the one which makes the most important discovery. We don't necessarily know which one that is yet.
Answer to:
Well i have to find out the square root of five for extra credit for a class. im thinkin its supposed to be a trick question but there must be some way to represent it other than a million digit decimal. help?
The square root of 5 appears in the golden ratio "phi".
phi = (sqrt(5) + 1)/2
Therefore sqrt(5) can be exactly represented as
2 phi - 1
The golden ratio is a curious number which comes up again and again. If you look at a pine cone, depending on how you look at it there are spirals going one way or the other. The ratio of the number of spirals going one way to the spirals...
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Answer to:
For the equation - 3x + 4y = 2. i got the slope is 3/4 and and the y-int= 2/4 but when i break it down it comes to 1/2 or .5. do i half to do the recipocal of 2/4 and make it 4/2?
-3 x + 4 y = 2
solve for y:
4 y = 2 + 3 x
y = (3/4) x + (2/4)
slope is (3/4)
y-intercept = (2/4) = (1/2)
You were right the first time.
Answer to:
How many 4 number combinations can be made from the numbers 1 to 28
If the numbers are all different, then you an select a set of four numbers from 28 in 28C4 ways
which is (28*27*26*25)/(4*3*2*1)
= 20475
You can then order those four numbers in (4*3*2*1) ways to make 491400 safe combinations.
If the numbers don't have to be different there are
(28*28*28*28) ways, which makes 615656 safe combinatiosn.
Answer to:
How do I find all solutions of the equation in the interval (0,2tt). 2 sin^2 x - 3sin x + 1 =0? I'm a real dullard at sin and cos. and I'm terrible with the unit circle.
Suppose I put s=sin x
So your question is
2 s^2 - 3s + 1 = 0
You can solve that, right?
That gives two possible values for s, which is sin x
Sketch a graph of sin(x) for your interval
draw on your values for sin(x) as horizontal lines.
Mark multiples of pi/2 on your x axis.
One horizontal line crosses the graph only once and you can read the value of x straight off the graph. The...
Answer to:
What rules exist when preforming operations on expressions involving square roots?( algerbra1)--multiplication/division and also add/subtract.
sqrt(A) sqrt(B) = sqrt(A B)
A sqrt(B) = sqrt(A^2 B)
sqrt(A) sqrt(A) = wait for it... A
sqrt(A) / sqrt(B) = sqrt(A/B)
sqrt(A) + sqrt(B) can't (usually) be simplified any further.
Answer to:
Can you answer -3x-2(8x+9y-3z)
Are you just supposed to simplify this?
-2(8x+9y-3z)
is
-16x-18y+6z
see?
then you can add on the -3x at the front to make
-19x-18y+6z
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Answer to:
Can you answer -5x[to the second power]-8x[to the second power]+8x+2
You can add the -5x^2 to the -8x^2 to make
-13x^2 + 8x + 2
Is that all you want?
Answer to:
Here's the F1 NAL (sic) number question from me until 9 December 2009. What springs to mind when I mention the number zero?
Owls
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Answer to:
Which of the following accurately describes osmosis? The more concentrated solution absorbs water from the less concentrated solution. The less concentrated solution absorbs water from the more concentrated solution. The less concentrated solution gets mo
How to remember it:
Nature tries to make them the same concentration.
But the solute can't move, only the water.
So all it can do is move the water to the more concentrated side to try to dilute it.
Answer to:
An elevator starts from rest with a constant upward acel and moves 1m in the first 1.8s. Apassenger is holding a 7.8kg bundle at the end of a vertical cord. The accel. of gravity is 9.8m/s^2.What is the tension in the cord as the elevator acels? anwr in N
The elevator travelled at an average speed of 1/1.8 m/s. It started from rest so it must end at (2/1.8) m/s
It accelerated to (2/1.8)m/s in 1.8s, an acceleration of (2/(1.8*1.8)) m/s^2
As the elevator is accelerating upwards things feel heavier inside. The tension in the cord gets bigger.
The force due to gravity (in N) is F=Mg = 7.8*9.8
The force due to acceleration is F=Ma =...
Answer to:
According to Einstein, "Energy can neither be created nor destroyed, but it can be transformed from one form to the other". When energy cannot be created, then where did the initial energy for Supernova /Big Bang come from?
There are some formulations which say that the total energy in the universe is zero.
To understand how negative energy can exist, think of a planet in an orbit. If we lift the planet away from the star and take it away we have to put in a lot of energy. So the planet in orbit situation is somehow missing some energy from the energy you would have if you just added a star + a planet. Add up...
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Answer to:
Accroding to Law of inertia, a body tends to move in the same line unless it is acted upon by another force. In space, the planets are revolving due to inertia, but when u say they are revolving, aren't they spending some energy ? If YES/NO, Why?
The kinetic energy of a body changes as force multiplied the distance moved along the direction of the force.
In math: delta_KE = F . delta_r
delta_KE is the gain in kinetic energy, F is the force vector and delta_r is change in position vector and '.' is the scalar product.
If the planet is in a circular orbit it loses no energy because the force is always exactly at right...
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Answer to:
If rectangles equal $0.50 and squares equal $0.25, what is the value of a rectangular prism?
A rectangular prism is like a building with a rectangular cross-section. It can have two square walls and two rectangular walls, or four rectangular walls.
Four rectangular walls + a rectangular floor and ceiling would make $3
But that's a hollow rectangular prism. Normally the prism is solid. There's a rectangle at every possible height width and length.
So really need to know...
Answer to:
Let the function k be defined be k(x)=5+2x^2 for all x, where x is an even integer. If the domain of the function k is -7<x<3, what is the largest value in the range of the function?
x can only take the values -6 -4 -2 0 2
There are only five.
You might as well compute k(x) for each of them and pick the largest.
Answer to:
Let the function f be defined by f(x)=4-x and let the function g be defined by as g(x)=5x-1. If the function h is defined by h(x)=2x+8, which expression represents f(g(h(x)))?
A) -10x-32
B) -10x-35
C) -10x+43
D) -10x+46
E) -10x+49
First rewrite your functions so they don't use x:
f(a) = 4-a
g(b) = 5b-1
h(c)= 2c+8
h(x) = 2x+8
g(h(x)) = 5(2x+8) - 1
f(g(h(x))) = 4 - (5(2x+8) - 1)
just by substituting for c,b,a in the function defintions.
Answer to:
Let the function f be defined by f(x)=2x+4 and let the function g be defined by g(x)=-3x+1. If f(2x+)=11 and g(x+2y)= 16, then x=...
First rewrite your functions so they don't use x and y:
f(a) = 2a+4
g(b) = -3b+1
now you x+2y instead of b in g(b) = 16
so replace b with x+2y:
-3(x+2y)+1 = 16
Do the same for the f equation.
Solve for x and y.
Answer to:
Here's the penultimate number question for Christmas. What springs to mind when I broach the number 337?
Oddly, nothing at all.
It feels prime.
Answer to:
What number goes into the blank? 9,61,52,63,94,__,18 please answer withproof thank you
Strictly speaking, any number can go in the blank.
You can find a formula which fits through any sequence of numbers you like.
It's curious that the numbers 61 52 63 94 form a perfect quadratic though.
If you ignore the first and last numbers of your sequence, the next number would be 145
EDIT: Starson obviously has the right answer. Square numbers written backwards.
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Answer to:
12 red candies, 12 blue, 7 green, 13 brown, 3 orange, and 10 yellow. 3 candies are pulled from the bag in succession, without replacement. Determine the probability that the first candy drawn is blue, the second red, and the third is green.
There are 57 in your list.
Probability that the first one is blue is 12/57
Now there are 56.
Probability that the second one is red given that the first one was blue is 12/56
Now there are 55.
Probability that the second one is green given that the first one was blue and that the second red is 7/55
Total probability = (12*12*7)/(57*56*55)
= (2*3*7)/(19*7*55)
= 42/7315
= 0.00574 or...
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Answer to:
Given: f(x) = 6/x, find and simplify (f(x+h)-f(x))/h. Please do it step by step so that I understand the concept.
f(x+h) = 6/(x+h)
f(x) = 6/x
need to subtract them.
Put them over a common denominator.
(6x - 6(x+h)) /(x(x+h))
simplify:
(-6h)/(x(x+h))
After the final divide by h:
(-6)/(x(x+h))
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Answer to:
The rate of decay of a radioactive isotope is directly proportional to the amount remaining. If the half-life of the radioactive isotope, Einsteinium, is 276 days and a sample initially weighs 25 grams, what is the rate of decay on the 120th day? Explain.
Amount left = 25 half^(days/276)
= 25 e^((days/276) log(half))
I used this rule: a^b = e^(b log a)
Instantaneous Rate = (25/276) log(half) e^(days/276)
I found the derivative, which is easy because e^(A x) becomes A e^(A x)
Now substitute days=120 to find the rate.
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Answer to:
A line tangent to the curve f(x)=1/2^2x at the point (a, f(a)) has a slope of -1. What is the x-intercept of this tangent? Please show and explain, thanks!
Find the derivative of f(x).
f '(x) = ?
You are given f '(a) = -1
solve for a.
Now imagine a line with slope -1 leading from point (a,f(a)). As you travel along the line, for every unit of x you travel, you drop one unit of y.
After you've travelled from "a" "f(a)" units, you will hit the x-intecept a + f(a) where y=0.
Answer to:
If g''(x)=x/(2+e^2) and g'(0)=-1, what is g'(3)? Please explain, and thanks!
Put h(x) for g '(x)
Now your question is one ' simpler:
h '(x) = x/(something)
and you want to know things about h(x)
h '(x) is the derivative of h(x)
so h(x) is an integral of h '(x)
Integrate h '(x) to give you all possible h(x).
There will be a constant of integration.
You know that h(0) = -1, so that will allow you to find the constant.
Then...
Answer to:
How do I rationalize denominators? (See first answer for specifics.)
Given your question: A / (sqrt(B) - sqrt(C))
I would multiply the numerator and denominator by
sqrt(B) + sqrt(C)
Then the denominator becomes the difference of two squares.
So you get (A (sqrt(B) + sqrt(C))) / ((sqrt(B) - sqrt(C))*(sqrt(B) + sqrt(C)))
which becomes:
(A (sqrt(B) + sqrt(C))) / ((sqrt(B)^2 - sqrt(C)^2)
which is
(A (sqrt(B) + sqrt(C))) / (B - C)
In your...
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Answer to:
Consider the function g(x)=tan(x+2) in the open interval -4<x<5. How many times are the tangents to g(x) parallel to the line y=2x-1? Please explain and thanks! These probs are killing me.
That line has slope 2.
You're looking for places where tan(x+2) has slope 2 in the range -4 to 5.
You probably should know that tan repeats every pi radians (180 degrees).
So you're expected to find the slope (derivative) of tan(x+2).
the "x+2" doesn't change the way you calculate the derivatve and tan x -> sec^2 x (or do it tediously from tan x = sin(x)/cos(x))...
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Answer to:
How many raindrops would it take to fill the oceans?
about 20 septillion.
That's 20 000 000 000 000 000 000 000 000
Answer to:
How many lines of summetry dose a iraq flag have
Without the central motto, one lines of symmetry: a vertical line through the midpoint.
Answer to:
When two dice are rolled, what is the probability of getting a 5 on the first dice and a 2 on the second
All the combinations:
1&1, 1&2, 1&3, 1&4, 1&5, 1&6
2&1, 2&2, 2&3, 2&4, 2&5, 2&6
3&1, 3&2, 3&3, 3&4, 3&5, 3&6
4&1, 4&2, 4&3, 4&4, 4&5, 4&6
5&1, 5&2, 5&3, 5&4, 5&5, 5&6
6&1, 6&2, 6&3, 6&4, 6&5, 6&6
Each of those 36 possibilities is equally likely....
Answer to:
What are the odds of getting at least 8 correct by randomly guessing while taking a 10 question T/F quiz? Then what about at least 7 correct?
10 correct = 10C10 * 2^-10 = 2^-10
9 correct = 10C9 * 2^-10 = 10 * 2^-10
8 correct = 10C8 * 2^-10 = 45 * 2^-10
7 correct = 10C7 * 2^-10 = 120 * 2^-10
nCr is the "binomial coefficient".
10C7 is the same as 10C3 which is (10*9*8) / (3*2*1)
So at least 8 = 56 * 2^-10 = 0.055 = about one chance in 18 or odds of exactly 121 to 7 against.
at least 7 = 176 * 2^-10 = 0.172 = about...
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Answer to:
Are there any integer solutions to the equation 74*x1+54*x2+57.5*x3+37.5*x4+20*x5= 1432
THANKS INDEED!
Interesting one. Double the question to leave integer coefficients:
148 x1 + 108 x2 + 115 x3 + 75 x4 + 40 x5 = 2864
if any two of these coefficients are mutually prime, then there you have an integer solution straight away.
148 and 75 are mutually prime!
You can find integer values for x1 and x4 leaving all the others zero.
You do it using the Euclidean algorithm:
148 *1 + 75 *0 = 148
...
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Answer to:
Can you show me how you arrived at your answer? 7+2|x - 3| ≤ 19.
7 + 2|x - 3| <= 19
2|x - 3| <= 12
|x - 3| <= 6
|x - a| means "the absolute distance of x from a"
if x can be up to 6 units from 3 then
x must be in the range [3-6,3+6] = [-3,+9]
Answer to:
Having finished with the Miss Deighton questions, here is the antepenultimate (i.e. middle) 'special festive number' question for Christmas. What springs to mind when you hear the number 225?
You know what I'm going to say by now, don't you?
Fifteen squared.
Answer to:
How many grams of water can be produced by the combination of 8 grams of oxygen and 8 grams of hydrogen?
The equation is
2 H2 + O2 -> 2 H2O
each of those represents one mole of the substance.
Molecular oxygen has an atomic weight of 32 grams per mole. Molecular hydrogen has an atomic weight of 2 grams per mole.
So the question concerns a quarter of a mole of oxygen, and 4 moles of hydrogen.
From the equation a quarter of a mole of oxygen (8g) combines with half a mole of hydrogen (1g) so...
Answer to:
Does adding salt make water retain its heat longer? example: a longer hot bath
Water has a very high specific heat capacity - it retains its heat very well and it takes a lot of energy to change its temperature. Adding a small amount of salt isn't gonig to make much difference, adding a lot of salt is probably going to reduce the effect.
However, if you do want a longer bath, add detergent ("bubble bath") and make bubbles. A layer of bubbles is an...
Answer to:
Wouldn't a 1000 watt refrigerator heat a room more efficiently than a 1000 watt electric heater? The refrigerator has effectively taken the cold from the room and locked it in an insulated box.
Ah! Yes you're right in the sense that the room heats up by the 1000J per second you put in PLUS some of the heat energy that was in the refrigerator.
The heat might be better distributed by the heater.
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Answer to:
According to an advertisement, The Jonas Brothers IQ score is 125. Now, is the each has 125, or does that mean they each have an IQ of 41.67?
The web seems to think they have an average IQ of 114, 116 or 122.
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Answer to:
Atoms of two or more elements that are chemically united form ________?
Two answers fit: molecules, compounds.
compounds are made of molecules.
Answer to:
An atom does not easily lose or gain electrons if it has_______?
A complete outer electron shell, such as in the noble gases.
Answer to:
How would you find escape velocity if an object is starting from a point 2000km above the planet it's leaving?
Use the potential equation E = -GMm/r
At infinity, there is no potential, as you get closer, the value of E becomes negative, meaning energy has been released. To escape you need to put that energy back in, so you need to put in a velocity with E = (1/2) m v^2
So v = sqrt(2GM/r)
G is the gravitational constant which is about 6.67 x 10^-11 m^3 kg^-1 s^-2
M is the mass in kg of the body...
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Answer to:
Would somebody please use the word "Kinematics" in a sentence?
I found this on google and I like it:
"The kinematic characteristics of the eating action in humans were assessed. Ten subjects were asked to bring to the mouth pieces of cheese ..."
Answer to:
How do I get my tools to de-ice my car (in the car)if car door that won't open? Hmmmmm!
Keep some tools in the house...?
Is the door or the lock?
I sometimes have to melt the ice out of the lock: Just pressing the palm of my hand against it, I have to keep changing position (and hand) to stop my hand freezing.
The pee-on-the-lock thing could be substituted with a lukewarm beverage perhaps.
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Answer to:
In the whole process of the transcription and translation of DNA, I've come to the point of tRNA turning the codon into a protein molecule. What happens from then? What does the molecule do to initiate traits?
The protein is usually an enzyme, which catalyses a reaction, which causes something to happen which perhaps wouldn't have happened otherwise - such as creating the brown pigment in your eyes.
Answer to:
Do electrical devices that use 1000 watts all heat a room identically? That is, would a 1000 watt heater heat the room identically to a 1000 watt motor or 10 hundred-watt light bulbs?
Yes and no. If the heat emitting parts were all the same shape then the heating would be identical for each
Otherwise they will differ in how they distribute the heat - you could have hotter spots and colder spots in the room.
But if you use the device and then allow time for the temperature in the room to even out, then all those devices heat the room the same.
The only exception...
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Answer to:
Why does the flow of water from a tap decrease when someone open another tap from a building.
Presusre is force per unit area.
The water pushes against the walls of the pipes and the inside of the tap with a force which is due to its depth below a water tower or tank.
Open a tap and some of that force is being used to force water out of the tap, so the pressure goes down, and the force available to push out water at another tap goes down also.
Answer to:
Was it really compulsory for Miss Deighton to count the beefburgers at lunchtime?
Do not worry, Miss Deighton is obsessed with counting.
Hopefully, this is a phase she is going through which will pass.
Answer to:
How do i the missing piece of information given the following information? Find the equation of the line that passes through the points (3, -1) and (2, 5). y = -6x + ? i dont want the ansrew but how to work it out. thanks
In (3,-1)
the 3 means that at that point x=3
and the -1 means that at that point y=-1
So your line equation y=-6x+c has become
(-1) = (-6)(3) + c
-1 = -18 + c
17 = c
If everything is working, the line equation will work for the other point too:
(5) = (-6)(2) + c
5 = -12 + c
17 = c
Answer to:
Why are 1,3,10,100,300, etc used as population thresholds?
Suppose 1, 10, 100, 1000 isn't fine grained enough.
What number x is mid way between 1 and 10 on this scale so that the ratio 1 to x is the same as the ratio x to 10
Answer sqrt(10) which is 3.16
So 1, 3.16, 10, 31.6, 100, 316, 1000, would be a
new scale. Obviously 3.16 has been rounded to 3 to make it easier.
As to why do you divide the 100-1000 range into exactly two pieces I...
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Answer to:
What does c=? if a=640 and b=1280; c is the hypotenuse of a triangle.
Only right triangles have a hypotenuse.
Pythagoras: c^2 = a^2 + b^2
c^2= 640^2 + (2*640)^2
c^2 = 640^2 + 4 * 640^2
c^2 = 640^2 * 5
c = 640 sqrt(5)
Answer to:
What does side b=?, if side a=640 and side c=1280 of a triangle?
Answer, by the cosine rule,
b = sqrt(a^2 + c^2 - 2 a c cos B)
b = sqrt(a^2 + c^2 - 2 a c cos B)
b = sqrt(2048000 - 1638400 cos B)
b = 640 sqrt(5 - 4 cos B)
where B is the angle opposite b.
If that's a right angle, then cos B is zero.
Answer to:
How do I begin to solve a problem like this? I have my X and Y variables.
__% of the variance of the sales can be accounted by the variance of advertising expenditure.
This might be wrong, but given that question I would compute the variance of the sales and the variance of the advertising expenditure.
Then I would find what the variance of the sales would be if it was entirely accounted for by the variance of the advertising expenditure: that is if the sales depended linearly on the advertising expenditure according to a linear regression, y=mx+c;
(the...
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Answer to:
When doing a Chi-Squared test, the sample size should be large enough so that the smallest expected cell frequency is at least ___.
Please explain how to answer this.
One goes here:
http://en.wikipedia.org/wiki/Pearson%27s_chi-square_test#Problems
and reads "Where there is only 1 degree of freedom, the approximation is not reliable if expected frequencies are below 10".
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Answer to:
In a box there are 4 chocolate bars, 3 gums and two mints. What is the probability that you pick a chocolate bar and a gum? I know I need to use the P(A) = n(A) / n(S) formula, and I'm pretty sure that the n(S) is equal to 9P2. I just don't know n(A).
n(S) is the number of ways of choosing two sweets, (indpendently of order), it is 9C2.
n(A) is the number of ways of choosing one chocolate bar and one gum. 4C1 times 3C1.
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Answer to:
Pearsons correlation coefficient for a certain set of data for 2 variables (x & y) is r=0.87 b=12.3 & a=1.5 (in correlation regression equation y=bx+a). Suppose we add 1.8 to each y-values & leave x-values same. New Pearsons coefficient of correlation is?
The value of a will increase by 1.8, and b and r will be unchanged.
This is probably easiest to see on a simple graph.
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Answer to:
A large truck can carry 7 of container A, 6 of container B, and 4 of container C. A medium truck can carry 6 of A, 3 of B, and 2 of C. The small truck can carry 8 of A, 1 of B, and 2 of C. how many trucks are needed to deliver 64 A, 33 B, and 26 C?
Look up "linear programming" also known as "linear optimization" which is how you solve a question like this one.
I could never remember how to do them, so I'll get back to you if I can work out an easier way of doing it!
EDIT:
Let L be the number of large trucks, M medium, and S small.
Need
7L + 6M + 8S >= 64 A containers
6L + 3M + 1S >= 33 B...
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Answer to:
How many ways are there to arrange a deck of 52 cards with no adjacent cards of the same suit?
I've been thinking about this.
I don't know if there's an easy answer.
I can estimate it:
Suppose that all cards in the deck could be picked at random from the 52 possible cards.
Then there are 52^52 combinations.
Consider the suits in this order: C D H S C D H S
Write down for each of the 51 adjacent pairs cards write down the number of cards you have to move right in...
Answer to:
When using parametric equations, what is the most often used papametric variable? x, t, $d or 0
t
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Answer to:
How many sequential values are there in a series whose difference is 3, begins at 2, and ends at 14, and whose sum is 40? 6, 4, 13, or 5
2 + 5 + 8 + 11 + 14
I'm not suprised you had counting the terms.
Forsooth, there must be more than three terms there!
Answer to:
Number questions never die - they only reappear during the festive season. So here's the second of 5 special number questions for the festive season - what springs to mind when I mention the number one hundred and forty three?
12^2 - 1^2 !!
= (12-1) (12+1)
= 11 thirteens
Answer to:
How far is a particle from is starting point after t=3seconds if x=tand y=t^2-5? 5 units, 7 units, -5 units, or can't be determined
if t=3
and x=t
and y=t^2-5
then you know that x=3
and y=4
Now draw the diagram showing the particle having moved 3 units right and 4 up.
Joing the particle to its starting point.
You should have a right triangle.
The easiest possible one.
Answer to:
(Solve for n.) n - 4 3/5 = 9 1/4? (fraction form)
n - 4 3/5 = 9 1/4
Add enough to both sides to get n on its own:
n = 4 3/5 + 9 1/4
Add the whole numbers and fractions separately:
n = 9 + 4 + 3/5 + 1/4
n = 13 + 3/5 + 1/4
the fractions will fit over a common denominator of 20
n = 13 + 12/20 + 5/20
n = 13 + 17/20
n = 13 17/20
Answer to:
Draw a diagram to solve. Penny draws pentagon ABCDE. She finds that LABE measurs 36º. She draws a line segment AF to bisect LBAE. What is the measure of LFAB?
All you need to know is if AB = AE
If this is true, then the pentagon is a red herring.
You will then have a isoceles triangle EAB and angle ABE equals angle AEB equals 36
Find angle BAE from the angles-in-a-triangle rule and bisect it.
Answer to:
Do you feel like a number?
No, I am a free man!
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Answer to:
What are the values of the indices i and j for the element that is in the fifth column and fourth row? 4,5 respectively: 5,4 respectively: Either 4,5 or 5,4 they are interchangeable or there are no elements in matrices
row number first.
Then column.
Answer to:
If a is 3x4 Matrix, B is a 4x12 matrix, and c is a 12x2 matrix, then CBA is: 13824, a 3x4x12 matris, a 3x2 matris or none of the above
Trick question, or stupid teacher.
To multiply matrix P with matrix Q
the dimensions must look like:
a x b and b x c and the result is a x c
Notice the adjacent "b and b" kinda cancels out.
So A B C would work, but not C B A
Answer to:
If A is a 3x4 matrice, B is a 3x4 matrix, and C is a 3x4 matrix, then A+B+C is a 9x12, 3x4, 27x64 impossible
It only makes sense to add matrices if they have the same shape. You then add the elements individually and end up with another matrix with the same shape.
Can you do it now?
Answer to:
I^-1= 0, I, 1, or you can't find the inverse of this matrix?
I is the identity matrix which leaves matrices the same on multiplication.
To find an inverse, you need to find A^-1 which when multiplied by A gives I
To find the inverse of I you need to find a matrix which when multiplied by I gives I.
... still stuck ... ?
I is the identity matrix which leaves matrices the same on multiplication.
repeat and fade...
Answer to:
Listing the irst ten digits of the pi is n example of a(n) series, arithmetic series, geometric series, or sequence
A series is a sum of a sequence.
Listing some numbers isn't a sum.
Listing some numbers is practically the definition of a sequence.
Answer to:
There are 30 children on a playground. What would be the probability that at least two of them share the same birthday?
What is the probability that NONE of them share a birthday?
First you have to choose 30 different birthdays from 365 days (foretting the complication of feb 29 as it won't make much difference)!
The formula for that is 365C30 which is read as '365 choose 30' and is calculated as (365*364*363*...*336)/(30*29*28*...*1)
there are 30 numbers in the numerator product, and in...
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Answer to:
What if you place 1000 marbles in a jar, each with a distinct number from 1 to 1000, never using the same digit twice. What is the probability that if you select one at random it will have the digit 3?
It is impossible to place 1000 marbles in a jar each with a distinct number from 1 to 1000 never using the same digit twice.
You'd have to use all the numbers from 1-1000 and 1000 contains the digit 0 three times.
I know what you meant.
The probability you want is P(marble has a number with a digit 3) = N(marbles with a a digit 3)/ N(total number of marbles)
How many marbles...
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Answer to:
I have an assignment question that asks: Evaluate lim (e^2x - 1)/(e^x - 1) as x tends towards zero. What is meant by evaluate?/how do i evaluate this equation?
evaluate means find the value of.
The numerator is the difference of two squares.
This can be factorized:
A^2 - B^2 = (A-B)(A+B)
So the numerator is (e^x - 1)(e^x + 1)
the denominator cancels and you are left with the question:
Find lim (e^x + 1) as x tends to zero
e^0 is 1 so the answer is 1+1=2
In a more complex case, you have to use the definition of limit to find the...
Answer to:
Finding the roots of a quadratic equation with leading coefficient greater then 1: 4x^2+25=20x
This can be solved using the middle term method which is described here: http://www.answerbag.com/q_view/1126040
But your question is easier than that:
4 is square
25 is square
Your equation is (2x - 5)^2 = 0
as 2*(2x*5) = 20x
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Answer to:
Find sin(a -b) if:
cos a = -8/17
sin b = -7/25
pi/2 < a, and pi < b < 3pi/2
My answer:
sin(a -b) = sin a cosb - cos a sin b
= (15/17 * -24/25) - (-8/17 * -7/25)
= - 360/425 - 56/425
= - 331/425
The method looks good.
Check:
a is about 118 degrees.
b is about 196.3 degrees.
a-b = -78.3 degrees
sin(a-b) = -0.979
But
-331/425= -0.778
Your answer doesn't seem to work.
Oh I see where you have gone wrong
-360/425 - 56/425 = -416/425 not -331/425
It was on the easy sum at the end, after you've done all the hard trig!
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Answer to:
Factor the following:First Expression 4y^2 -12y +4yz - 12z. Second Expression x^2 -2x -3. Third Expression10x^2 +26x -12
The second and third expressions can be solved using the "middle term" method which is explained here:
http://www.answerbag.com/q_view/1126040
For the first one, well there's a factor of 4 making
4(y^2 - 3 y + yz - 3z)
And now I can see that the bracketed part is in two similar pieces. The left two terms have a y where the right two have a z:
4(y+z)(y-3)
Answer to:
Trigonometry: prove tan q = csc2q - cot2q?
I am struggling with this one, can anyone show me how it is done?
I always convert to sines and coses first.
so
tan q = csc(2q) - cot(2q)
becomes
= (1/sin(2q)) - (cos(2q)/sin(2q))
= (1 - cos(2q)) / sin(2q)
Trig formula:
sin(A+B) = sin(A)cos(B) + sin(B)cos(A)
so:
sin(2q) = 2sin(q)cos(q)
Trig formula:
cos(A+B) = cos(A)cos(B) - sin(A)sin(B)
So:
cos(2q) = cos^2(q) - sin^2(q)
or 2 cos^2(q) - 1 (use cos^2 + sin^2 = 1)
or 1 - 2...
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Answer to:
Trigonometry: prove:
tan3a = cosa - cos5a/sin5a-sina
It throws me for a loop when proofs have integers in the functions. Studying for a test and got this own wrong on my mid term, please explain thanks!
Trig formula for subtraction of cos and sin:
cos(A) - cos(B) = - 2 sin((A+B)/2) sin((A-B)/2)
sin(A) - sin(B) = 2 cos((A+B)/2) sin((A-B)/2))
Using these:
tan 3a = (cos a - cos 5a) / (sin 5a - sin a)
= (-2 sin(3a)sin(-2a))/(2cos(3a)sin(2a))
= (sin(3a)sin(2a))/(cos(3a)sin(2a))
= sin(3a)/cos(3a)
= tan(3a)
It is possible to work out the formula as long as you remember just these...
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Answer to:
How do I solve f(x)=-6x-18?
It means put f(x) = 0
put - 6x - 18 = 0
There's 6x missing from the left hand side.
add 6x to both sides of the equation.
divide both sides by 6.
See what you get.
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Answer to:
Find range of 1+3cos2x
sin or cos of anything varies no more than -1 to +1
so 3cos something varies from -3 to +3
so 1 + 3cos something varies from -2 to +4
Answer to:
A power network involves 3 substations A,B, and C. overloads at any of these result in a blackout of the entire network. past history has shown if substation A alone experiences an overload, then there is a 1% chance of network blackout. for stations B
Nice to see you again.
These ones you usually work out by negating the events: so you work out the probabilities that the events do not happen.
If the events are indpendent, the probability that NONE of the events happen is P(not A) * P(not B) * P(not C)
then you do 1-that to find out the probability that at least one event happens.
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Answer to:
I have a 24 inch dia pipe and need to cover all but 140 sq inches up. What is the formula?
Cover it all up, cut a 10" x 14" rectangle.
The diagonal of the rectangle is sqrt(244) ~= 15.6" so it will easily fit.
Or you could cut a hole with diameter 2sqrt(140/pi) ~= 13.4"
If you want to cover by filling to a given height, there is no exact formula that can give you the value for h, but you can find it by numerically solving:
A = r^2 arccos((r-h)/r) - (r-h)...
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Answer to:
3(2x+9) what does the x stand for or what two number does it stand for also what is the sixth prime number
The first six primes are 2 3 5 7 11 13
In another question, you suggest that 3(2x+9) = 147
If three times (2x+9) is 147,
then (2x+9) must be one third of 147 or 49
if nine more than 2x is 49
then 2x must be nine less than 49 or 40
if twice x is 40, then x must be half 40, or 20.
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Answer to:
Need help: The equations of three circles are x^2 + y^2 - 2x - 4y -4 = 0, x^2 + y^2 - 8x + 4y + 16 = 0 and 4x^2 + 4y^2 - 48x - 16y + 135 = 0. Find the number of points common to at least two of the circles.
If you divide the fourth equation by four, all equations have x^2+y^2
the next two terms divided by -2 give the center of the circle:
-2x-4y means the center is at x1 y2
By rewriting the equation in the form:
(x-1)^2 + (y-2)^2 = r^2
you can find the radius.
The first equation is:
((x-1)^2 - (1)^2) + ((y-2)^2 - (2)^2) - 4 = 0
(x-1)^2 + (y-2)^2 = 4 + (1)^2 + (2)^2 = 9
radius is 3....
Answer to:
Here's the second of 5 special number-related questions. What springs to mind when you hear the number eighty two?
9^2 + 1^2
Darn it, clearly I am a math geek!
Answer to:
Grade 11 trigonometry: tan33 = h/((h/square root of 3) + 500) I know the answer is 519 but I don't know how to go about solving it. Please explain?
Step by step:
tan(33) = h/((h/sqrt(3)) + 500)
multiply both sides by the denominator on the right
tan(33)((h/sqrt(3)) + 500) = h
distribute/expand:
(tan(33) h / sqrt(3)) + 500 tan(33)= h
Multiply through by sqrt(3) to remove the denominator.
tan(33) h + 500 tan(33) sqrt(3) = h sqrt(3)
Collect terms involving h by subtracting tan(33) h from both sides, and factoring:...
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Answer to:
3 2x 9=147 what is the sixth prime number and what number does x stand for
The first six prime numbers are
2 3 5 7 11 13
147 = 3 times 49
So if 2x is supposed to stand in for the 4 in 49, then x must be 2.
But it's not a valid math question: you can't put variables to stand for PARTS of a number. A mathematician would have to write an expression to split up the number, something like this:
3 times ((10 times 2x) + 9) = 147, what is x?
Answer to:
What does 'biased' mean in terms on Mathmatics?
In school math, the word biased is often applied to the word die or dice. biased dice do not give out each number with equal probability.
In statistics an unbiased estimate is one where the average of a large number of similar estimates would get you as close as you like to the true value.
An example of a biased estimate would be to estimate the standard deviation of a population by using...
Answer to:
How do you factor this: 6y^2 + 9y + 4xy + 6x?
If you want to know how to do this is done in general, look up Groebner bases ( or Gröbner bases ), that's probably way beyond what you need.
One way of factoring is to look for expressions which are zero, when the expression is zero.
So: 6y^2 + 9y + 4xy + 6x = 0
The expression is less complicated in x, so try solving for x:
(4y + 6)x = -(6y^2 + 9y)
x = -(6y^2 +...
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Answer to:
Another one thats probably easy but i just don't get it
Evaluate e^4 + e^-4/10^4 do i just calculate this or is there more to it?
e^-4/10^4 = 1/(10000 e^4)
perhaps that's the idea, that you can use e^4 twice.
If it is supposed to be (e^4 + e^-4)/10^4,
e^4 + e^-4 is 2 cosh(4 radians)
I don't know if that's helpful?
What are the adjacent questions like?
Answer to:
What form is the equation y=5-3x in? How do I convert this to slope- intercept form? The question is asking me to find a line parrallel to this one.
Slope intercept form is usually
y = m x + c
So you only need to swap the 5 and the -3x to get
y = -3 x + 5
giving slope, m = -3 and, intecept, c = 5.
A parallel line would be similar but with a different intercept.
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Answer to:
Find the volume common to two spheres, each with radius r=6 if the center of each sphere lies on the surface of the other sphere.
It would be helpful to know the volume of sphere below a plane.
If you imagine the sphere sinking into an energy field that vaporizes a slice of sphere of height dh every second, then the volume vaporized is pi r^2 dh, where r is the radius of the disk that is being vaporized.
if h is the height of sphere that has been eaten, r^2 is R^2 - (R-h)^2 by Pythagoras, where R is the radius of the...
Answer to:
What are the MOST common types of resistors?
Thick film
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Answer to:
A point on a graph is (2,-3).that point is located in
The fourth quadrant.
Sketch a quick graph, draw in the one point that has x=2 (two units to the right of the origin) and y=-3 (three units below the origin).
You've drawn a point in the bottom right quarter of the graph. The quarters are called quadrants, and they are numbered anticlockwise, 1st, 2nd, 3rd, 4th starting at the top right.
Answer to:
Find the slope of the line that passes through the points (-3,-5) and (-5,1)
slope is always increase in y divided by increase in x
Between your poiints, there was an increase in y of 6 and a decrease in x of 2
increase in y = 6
increase in x = -2
slope = 6/-2 = -3
Answer to:
If the measure of a polygon is 16cm by 24cm, what is the measure of a polygon 1/2 the size
What does "half the size" actually mean?
Half the height? Then maybe 16cm by 12cm
Half the area but the same shape? Then roughly 11.31cm by 16.97cm
Why do I keep seing this "the measure of" phrase?
It doesn't seem to mean anything.
Is it a specific school, or a particular exam board?
Answer to:
If a regular pentagon with 3-centimeter sides has an approximate area of 15 centimeters squared what is the aproximate length of the apothem to the nearest hundreth?
wikipedia:"The apothem of a regular polygon is a line segment from the center to the midpoint of one of its sides"
The pentagon can be split into five triangles arranged around the center. Each will have area approximately 15/5 = 3cm^2, and the base of these triangles is a side of the pentagon: 3cm
Area of a triangle = half the base times the height.
Height = twice area / base...
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Answer to:
830 exceeds eleven times a number by 82. what is the number?
Without algebra:
If 830 exceeds eleven times a number by 82,
then 830 is 82 greater than eleven times a number.
eleven times a number is 82 less than 830
eleven times a number is 52 less than 800
eleven times a number is 50 less than 798
eleven times a number is 0 less than 748
eleven times a number is 748
a number is 748/11
a number is ((100*7)+48)/11
a number is ((99*7+7)+48)/11...
Answer to:
If a^n+1 is prime for some number a>=2 and n>=1, show that n must be a power of 2
Well my thought is suppose n isn't a power of 2.
Suppose it's 3.
a^3 + 1
No, that's not prime. if n is odd and n>=3, then I can factorize like this:
(a + 1) (a^2 - a + 1)
and both numbers are greater than one, so a^3+1 can't be prime.
What if n is 6?
a^6 + 1
Well now I can just write that as (a^2)^3 + 1
which we know will factorize the same way:
((a^2) + 1)...
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Answer to:
A man and a boy who are walking together step out with their right feet first. The boy walks three paces while the man walks two. When will they both put their left feet forward together?
Man, Boy
_R, _R
__, __
__, L_
L_, __
__, _R
__, __
_R, L_
__, __
__, _R
L_, __
__, L_
__, __
_R, _R back to where we started.
So, never.
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Answer to:
The measure of an angle is one third the measure of its supplement. Find the meausre of the angle.
The supplement is 180-angle
so
angle = (1/3) ( 180 - angle)
Solve for angle:
Multiply both sides by 3.
Add angle to both sides.
Divide both sides by four.
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Answer to:
Y = 3x + 5 crosses the y axis? how do i solve this equation to get the right answer? thanks
The Y axis has x=0 all along its length
So solve for x=0
Y = 3*0 + 5
Y = 5
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Answer to:
If you are in a spaceship and it turns on its side do you
If your spaceship is in freefall, there is no up, down or side.
If your spaceship is on the ground, you'll fall over.
Answer to:
Which anagram isthe odd one out ? inch keen earth fringe satchmo throne
They are all parts of the body:
chin
knee
heart
finger
stomach
throne... well it's probably in there somewhere.
Answer to:
Find the exact value of
-2log2^4
Could do with some brackets in your question!
Perhaps you wrote - 2*(log(2^4))
which is -8*log(2)
But logs to what base?
Well it happens that unless the base is a power of two, there is no exact answer for log(2), so I'll assume you want log to base 2 or lg(2) and lg(2) = 1 so the answer is -8.
Answer to:
What is the probability when randomly choosing 4 points in space (3D), bounded by x = [0,R], y = [0,R] and z = [0,R], so that all 4 points making up a totally stable tetrahedron [all 4 points will be contained within its bases, looking from its upside].
I don't think this is an easy question.
I would approach it like this:
Draw planes normal to each base through each side of the base. This divides the cube into an inside and an outside, compute the fraction of the volume inside, compute the distribution of the volume fraction.
This gives you the answer for ONE base.
Unfortunately it looks as though the results for two different...
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Answer to:
19. By exhibiting a counterexample, show that the following statement need not be true: if A and B independent events, and B and C are independent, then A and C are independent. Hint: Consider cases where A \ C = 0
It's easier NOT to use the hint:
Suppose that A and C are THE SAME EVENT, and B is independent of it.
A and B are independent, that's ok.
B and C are independent, that's ok.
A and C are 100% dependent!
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Answer to:
What is the equation of a vertical line that has an x-intercept of -3
x=-3
Answer to:
Prove that every tree with two or more vertices is 2-chromatic.
If you can't do this, you should probably drop graph theory. Elementary graph theory contains only two difficult proofs: The planar graph theorem, and Euler's formula. This isn't either of those.
2-chromatic means you can assign one of 2 colors to each vertex so that no two vertices are directly connected that have the same color.
A tree can be built recursively by adding a...
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Answer to:
What is the indefinite integral of cos(x) with respect to y?
It depends on the relationship between x and y.
If x and y are known to be unrelated, then the answer is
cos(x) y + C, you just treat cos(x) as a constant.
If y = cos(x), for example, then the answer would be
cos^(x)/2 + C, I just integrated y wrt y and substituted.
In general, if dy/dx = h(x)
then the integral of cos(x) dy = the integral of cos(x) h(x) dx
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Answer to:
Can you explain how euclidean geometry is flawed?
I'm not sure what you mean, Euclidean geometry isn't flawed! But you might mean:
a) Euclid derived his principles of geometry from five axioms. But he unsuspectingly made use of other unstated assumptions, the most famous of which is Pasch's axiom, if you draw a line (infinite line) that passes through one edge of a triangle and misses the corners, it must pass through one of...
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Answer to:
It has been reported that 3% of all cars on the highway are travelling at speeds in excess of 70mph. If the speeds
of four random automobiles are measures via radar, what is the probability that at least one car is going over 70mph?
It's easier to do these ones in reverse:
97% of the time, the first car is not travelling over 70mph.
Of those 97 out of every 100 occasions, in 97% of them, the second car is also not travelling over 70mph.
Of those (97/100)*(97/100) occasions, in 97% of them, the third car is also not travelling over 70mph ...
...
In (97/100)*(97/100)*(97/100)*(97/100) occasions none of the four...
Answer to:
Have you ever wondered why it is "one answer" but "zero answerS" when zero is less than one therefore not plural?
The pattern is "There are N answers" and really it is short for something like "the count of answers is N".
This sentence would still be fine if N was one.
But if you write "one" in front of "answers" it looks odd, because we are used to using the word "answer" when we mean one.
So perhaps the solution is "There are one...
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Answer to:
Let's play! Tails=t, Heads=h. What do you think, the following sequence of "t"-s and "h"-s is a real range of a coin tosses or only an imitation of it? thhhhtttthtthtthhhttthhthttttththhhththhthtttht I write the answer after getting 10 bets.
Nice question: any possible arrangement of heads and tails could come up by chance.
BUT the human being cannot produce a very random sequence so some sequences are more likely than others.
The number of heads and tails is about right. The number of runs of 1,2,3,4,5 is about right.
Putting them in rectangles doesn't show any patterns.
So I'm betting random, and if it's...
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Answer to:
What is a surd?
A surd is a number of the form
a + b sqrt(n) where a and b are rationals, n is an integer, and usually stays the same for the entire problem.
Surds are special in that multiplication, division, addition and subtraction of surds with the same value of n leads to another surd with the same value of n.
Complex numbers are a special kind of surd.
Some generalize the idea of surd to...
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Answer to:
What is an ellipsis?--fifth grade math?
An ellipsis is three dots. And it is used in math as it sometimes is in English to mean stuff was left out, that you are supposed to be able to work out from the context.
But the word "ellipsis" is not used in math. So I think you may be confusing this word with "ellipse" which is simply a circle which has been stretched linearly in one or more directions.
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Answer to:
What does the "one standard deviation" part mean in a sentence like the following... "the mean income of princes is *one standard deviation* greater than the income of dukes"?
Not all dukes have the same income.
There is an average income for dukes. Call it M.
Then a "standard deviation" is the average difference of a duke's income from M.
It's a measure of how "scattered" the incomes are.
If all dukes DID have the same income, the standard deviation would be zero.
If there were two dukes with incomes of $100,000 and...
Answer to:
Solve algebraically: sin 2x = -1/2
First, I get an approximation of the answer so I know what the answer should look like:
The sin(t) curve crosses the -1/2 line twice between 180 and 360 and as sin is periodic, you can add any multple of 360 and get the same answer. sin is also symmetric about 270 degrees, so if t is an answer 540-t is also an answer.
so sin(2x) will cross the -1/2 line twice between 90 and 180 and you...
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Answer to:
Why can't you have a shape with only 2 sides?
A spherical shell has two sides: an inside and an outside.
In two dimensions, a circle has an inside and an outside.
A solid convex lens shape can have two sides.
In terms of polygons, an octagon has 8 sides, a triangle 3 sides, and the "polygon" with two sides consists of two coincidental line segments with opposite sense. Mathematically, it's a perfectly good polygon,...
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Answer to:
What, in mathamatical terms does uniquely determined mean?
The criteria are enough to narrow down a specific single item from a set of items.
Example. In the set containing only "red grape", "green apple", "orange", "banana"; the fruit is uniquely determined by its color.
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Answer to:
What is the integral from -1 to 1 of (1-x^2)^(1/2)?
Without even attempting to work it out, the answer's going to be pi/2.
y = sqrt(1-x^2) is the equation of a semicircle of radius 1, and you're asking for the area under it.
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Answer to:
3 math books, 2 art books, 3 English books.
how many ways all 8 books on shelf
how many ways if grouped together
ways of group by subject matter?
The subjects could come in any of six orders:
MAE, MEA, EAM, EMA, AEM, AME.
The 3 math books could come in any of six orders.
The 3 english books could come in any of six orders.
The 2 art books could be either way round.
So there are 6*6*6*2 = 432 ways of arranging the books and still be grouped by subject matter.
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Answer to:
How do you find the value of the 20th percentile if the range of numbers are...say...?
139,143,220,227,183
You can't accurately work this out with only five data values.
The 20th percentile is the point that splits the population into "the lowest fifth" (lowest 20 hundredths) and "the highest four fifths"
You can tell from your numbers that the 20th percentile probably comes between 139 and 143, since that would split off the lowest fifth of your numbers.
Answer to:
What is 1 3/8 multiplied by 10?
1 and 3/8 multiplied by 10
is 10 and 30/8
which is 13 and 6/8 (because 30 is 8*3+6)
which is 13 and 3/4
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Answer to:
This is a question about the logic of two opposing positions on how to apportion a single property tax bill on land that was subdivided and now owned by two people. Please read the first answer which details the question itself and post your comments.
It's an interesting question.
Both parties probably agree that in future, they will have to pay $2000 each, because that is the tax due on property assessed as worth 500K.
This year, because of a peculiarty of the way the city works, one person picked up the entire bill of $3000
Since both parties agree that the tax bill for the properties will be in equal parts in future, due to...
Answer to:
What was my overall mark before the exam? the math exam was worth 30% of our overall mark.
on the exam i scored 52.5 out 113. after the exam, my overall mark became a 54% in the end.
but what was my overall mark BEFORE doing the exam?
Ok. The equation is:
54% = (52.5/113)*30% + (oldpercent/100)*70%
oldscore = 5400/70 - (5250*30)/(113*70)
= 57.23%
Another way of working it.
If 30% is 113 points worth,
then 100% is 376.67 points worth,
and there were 263.67 points to get before the exam.
At the end you got 54% which is 203.4 points.
52.5 came from the exam. You must have had 150.9 already.
150.9/263.67 = 0.5723 =...
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Answer to:
Suppose that you wanted to use this row [-2 4 6 | 14] to eliminate as many elements as possible in this row [2 4 -6 1 | 12]; how would you do this?
Add them.
Probably.
At least it looks as if the 2s and the 6s will cancel.
But.
The problem is your two rows aren't compatible: four numbers in the first and five in the second. You're missing a number or have one extra.
I suggest you just look at each number to see what you would have to do to cancel it, then see what other numbers will cancel.
In reality you NEVER look for...
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Answer to:
What is the minimum number of unique pints that are requird to determine th equation for a cubic? 1, 2, 3, or 4
There are four degrees of freedom in a cubic:
a x^3 + b x^2 + c x + d
a,b,c,d are all to be decided.
So you'll need four equations to find them.
Which means you need four points.
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Answer to:
Can anyone start the following equation as a matrice? 24a + b = 10 90a + b = 14
It nearly is already.
(24 1)(a) = (10)
(90 1)(b) = (14)
Answer to:
How many ounces of a 25% acid solution should be mixed with a 50% acid solution to produce 100 ounces of a 40% acid solution?
Say a the 25 and b of the 50
a+b = 100
Acid in a is 0.25a
Acid in b is 0.50b
Total acid is 0.25a+0.50b
and this is 0.40 of 100 = 40
multiply it by four to eliminate the decimals:
a + 2b = 160
subtract the first equation:
b = 60
so a = 40
check:
0.25 of 40 is 10 ounces of pure acid.
0.50 of 60 is 30 ounces of pure acid.
40 ounces of pure acid in 100 ounces of solution is 40%
Answer to:
A solution is 60% salt. i want a solution containing 45% salt. what amount of original solution do i have to take out and add back as pure diluted water to get the 45% salt solution?
Suppose you have Y pints of solution.
Take away X % of the original solution. = (X/100) * Y
You have ((100-X)/100)*Y left
of which (60/100)((100-X)/100)*Y is salt
Add back in (X/100)*Y of water.
You now have Y pints of solution again, of which
60((100-X)/100) percent =45 is salt.
60(100-X) = 4500
100-X = 75
X = 25% = one quarter of the solution.
I should have seen this sooner....
Answer to:
When blenders are sold for "p" dollars apiece,ppl will buy a total of 8000/p blenders a month. "t" months from now the price of blenders will be "0.04t^(3/2) +15 dollars. find the rate at which the monthly demand for bl
"Find the rate at which the monthly demand for blenders will decrease" (seeing as the price 0.04t^(3/2) increases)
Price of blenders at time t = 0.04t^(3/2) + 15
demand for blenders = 8000/(0.04 t^(3/2) + 15)
Assuming that the price and demand changes continuously,
The (negative) rate of increase is obtained by differentiating this eqaution with respect to t.
- 8000 ((3/2)...
Answer to:
If y = 8, then y8(y8-y)=?
y8 is not a usual way of writing a product. Numbers come before the letters in a product.
Perhaps the 8 was a subscript or a superscript and "cut-and-pasting" hasn't copied the formatting information.
If the 8 is a subscript then it is written in text as y8 or y_8 and simply means another quantity distinct from y.
Since we're not given y8 we cannot find the answer.
...
Answer to:
If a pill bottle contains either a clonazepam or clonidine pill and
then a clonidine pill is added & the botttle is shaken up and a
clonidine pill is "dumped" out, what are the chances a clonazepam pill
remains in the bottle?
Take four days, and MARK the clonidine pill you add to the bottle.
On day one, the bottle contains clonazepam, you add marked clonidine and dump out marked clonidine leaving clonazepam.
On day two, the bottle contains clonazepam, you add marked clonidine and dump out clonazepam leaving marked clonidine.
On day three, the bottle contains clonidine, you add marked clonidine, and dump marked...
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Answer to:
When solving a linear inequality why do you always solve for y?
Because teachers have no imagination?
Answer to:
How did the universe begin? without the bigband how the was the big band made?
I imagine that the conductor advertised for instrument players and they had an audition...
You really want to know, check out 'M-Theory'
http://en.wikipedia.org/wiki/M-Theory
Some string theorists say that our universe was created when two wandering mem-branes collided.
More info on the Big Bang: http://en.wikipedia.org/wiki/Big_Bang
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Answer to:
Help Please! "Determine which two functions are inverses of each other. The problem is : f(x)=5x, g(x)=x/5, h(x)=5/x ...what is the answer.....
f and g are functionally inverse.
f multipies by five
g divides by five.
These are opposites (inverse).
g and h are multiplicatively inverse.
f(x)*g(x) is 1.
Answer to:
1.Consider d(x)=(x+2)^3+3; what is the new equation for d(x) if it is 4 times larger?
2. What is f(x) if f(x) =z(x)+2 and z(x) =2x-3?
1. d(x) = 4((x+2)^3+3)
2. f(x) = z(x)+2 = (2x-3)+2
You don't _have_ to simplify those...
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Answer to:
A single die is tossed and if the face value is either 2 or 5 the result is deemed a success, otherwise it is a failure. If the die is tossed 5 times, what are the probabilities of getting exactly 3 successes, 4 or more successes, no successes?
The event "either 2 or 5" happens one third of the time.
p=(1/3)
The probability of p not happening, q, is (2/3)
The binomial distribution says that the probability of i successes in n tosses is given by
P(i sucesses) = nCi p^i q^(n-i)
where nCi is the "binomial coefficient"
5C3, for example, is (5*4*3)/(3*2*1)
You'll also need to know that anythingC0 is...
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Answer to:
Find the domain and range for f(x) = x^2 + 11.
domain = valid values for x as a subset of the available numbers. If this is a function of reals, then all real numbers are valid. [-infinity,infinity]
range = range of values which f(x) takes.
The smallest is 11 and all values above that are also allowed.
[11,infinity]
Answer to:
Is 10,000 million the same as 10 billion?
Yes, in most countries using the "short scale", including the USA, and the UK since 1974.
Some countries till use the "long scale" where a billion is 1000 times bigger.
See http://en.wikipedia.org/wiki/Long_and_short_scales
Answer to:
Prove L'Hospitals' Rule.
I know l'Hôpital's Rule.
I'd never heard of Hospital Rule until I looked it up.
Apparently "ô" is sometimes written "os" just as "ä" is sometimes written "ae".
l'Hôpital's Rule states that
If K = lim x->a f '(x)/g '(x) exists and is finite or infinite, and f(a) = g(a) = 0, then
...
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Answer to:
If the integer lengths of three sides of a triangle are 19, x, and 11, what is the least possible perimeter of the triangle?
The triangle inequality says that
a + b > c
where a b and c are any three sides of a triangle.
Alternatively a+b>=c if you allow degenerate triangles
So putting a=11, b=x, c=19
I get x>8
The perimeter, P =a+b+c > 11+8+19
P>38,
The smallest integer P>38 is 39
(or you get P=38 if you allow degenerate triangles)
Answer to:
What has CERN found from the experiment until now
There isn't enough data to discover anything from the experiment itself yet.
But there were lots of new technology and discoveries in building the experiment. Here is a list:
http://technologytransfer.web.cern.ch/TechnologyTransfer/en/Technologies/List_of_Available_Technologies.html
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Answer to:
If Hg has 1.23x10^23 atoms how many moles does it have?
One mole = 6.022 x 10^23
Answer: 1.23/6.022 moles.
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Answer to:
What kind of changes occurs when sodium chloride dissoves?
"physical ones" rather than chemical ones.
The sodium and chloride ions detach from the solid and are free to wander in the liquid.
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Answer to:
How can u explain A=1/2bh
Area of a triangle = half the base times the height.
If the apex of the triangle is above the base, draw a rectangle sitting on the base which just encloses the triangle touching the apex. Draw a vertical line from the apex dividing the triangle in two.
The rectangle has area base times height.
The area of the left side of the triangle is half the rectangle on the left.
The area of...
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Answer to:
How do you find the inverse function?
2X+1 all over X.
and/or
5 all over the square root of X.
Put y= your formula.
Like y=5/sqrt(x)
Now solve the equation for x as if y was a known quantity:
y sqrt(x) = 5
sqrt(x) = 5/y
x = (5/y)^2
The function f(y) = (5/y)^2 is the inverse function
[which is the same function as f(x) = (5/x)^2 ]
Answer to:
12 - (3x+2) = 5(x-2) + 4. i got 5/2 is that right?
Check your answer by substituting 5/2 for x:
12 - (3(5/2) + 2) = 5((5/2) - 2) + 4
12 - (15/2 + 4/2) = 5((5/2) - (4/2)) + 4
12 - (19/2) = 5 (1/2) + 4
24/2 - 19/2 = 5/2 + 8/2
5/2 = 13/2
5 = 13
Not right.
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Answer to:
Simplify the expression by distributing and combining like terms: -5 -2(x+3) + 7x how do i do this?
Look at this part:
-2(x+3)
If you have negative two of (x and 3)
you must have negative two of x and negative two of 3.
-2x + -2*3
This is "distributing" multiplication over addition.
Put the result in:
-5 -2x + -6 + 7x
Same as:
-5 + -6 + 7x - 2x
because I can change the order of addition - "commuting".
Same as:
(-5 + -6) + (7x - 2x)
Which is -11 + 5x
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Answer to:
Because of an incredible stroke of genius i have invented the greatest useless thing ever. What is it?
This question.
http://www.answerbag.com/q_view/1078166
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Answer to:
Can someone explain why a red light used in a darkroom does not affect the film during developing?
The important thing about the light is that it is very dim.
Then if you choose a color of light, you use red because the film is least sensitive to red light.
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Answer to:
How do we know that supergiants are larger than giants?
Radio inferometery can measure the sizes of the nearer supergiants.
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Answer to:
How would you use a copy machine that only allows reductions by 50-200% to reduce the document by 36% of original size
Do 72% then half it.
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Answer to:
If Rick can mow a lawn in 2 hours and Steve can mow the same lawn in 90 minutes, how fast can the lawn be mowed if they both work together? How is that figured?
The easy way to do this is in "lawns per hour".
Rick mows lawns at half a lawn per hour.
Steve mows lawns at (2/3) of a lawn per hour.
Together they mow at (1/2) + (2/3) = (3/6) + (4/6) = (7/6) lawns per hour.
So one lawn will take (6/7) hours or about 51 minutes.
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Answer to:
A board ten feet long is cut into two pieces. Three times the length of the shorter piece is twice the length of the longer piece. Find the length of each piece.
As an equation system, let S and L be the two pieces.
3S = 2L
and
S+L = 10
Two equations in two unknowns.
It's easier to solve it by thought:
Imagine three shorter pieces in a row and two longer pieces in a row. Both these lengths are the same.
They're like thirds and halves of a number. Break the number into sixths and two of the sixths make a short piece and three...
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Answer to:
When tap water from coventry is left overnight, bubbles appear on the side of the glass and the water tastes bleachy, this does not happen with the tap water in wales. why is that? is it to do with the fluoride levels?
Coventry water has more chlorine in it.
It maybe that, like North Birmingham, it gets its water from the Staffordshire bore holes.
Answer to:
Two parallel wires, each carrying a current of 2 A, exert a force per unit length on each other of 1.6X10^-5 N/m. what is the distance between the wires?
The formula is
Force / length = mu_0 I1 I2 / (2 pi d)
so
d = mu_0 I1 I2 / (2 pi (force_per_length))
Answer to:
What is the chemical's name and formula? Clues: the one cation and two anions each have 18 electrons. Pickled products and olives contain this chemical.
Argon has 18 electrons, so looking for a anion to the left of argon (fewer protons) and an cation to the right.
There are two anions to the cation, which implies twice the charge on the cation.
So go for 2+ on the cation and 1- on the anion which leads to Calcium Chloride
http://en.wikipedia.org/wiki/Calcium_chloride mentions its use in pickles. Close enough for me.
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Answer to:
Is it a valid proof of Fermat's Last Theorem? http://www.geocities.com/vala_var/
It's EXTREMELY unlikely.
Fermat's Last Theorem took many many years for Andrew Wiles to solve, who was an expert in that field.
The mathematician Kummer spent most of his life trying to prove it.
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Answer to:
1 what is the next number in the sequence of:
1, 1/2, 5,10,1/2, 18
I suspect the sequence you meant was 1 1/2, 5, 10 1/2, 18
without the extra commas. It would then be strictly increasing. In fact the sequence is (2x^2 + x)/2.
and the next number would be (2*5*5+5)/2 = 27 1/2
Answer to:
In triangle pqr measure angle p=x measure q=x+20 measure angle r=2x+20
To solve equations with unknown quantities, you usually need as many equations as there are unknown quantities.
The missing equation in your set is
p + q + r = 180 degrees
You know why this is equation is true, right?
Answer to:
How do I find the slope of the tangent line from a critical point? g(x)=2+4x(4-x) I solved for the 1st derivative for the critical point, 2. Now how do I find the slope of a tangent line from this, and two points where the average rate of change is 0.
A critical point is a value for x where g ' (x) is zero or where g is not differentiable.
So you found the critical point 2.
The slope of the tangent line at a point x is the same thing as g ' (x) at that point, so you already have the answer to this since you the x you found was the point at which g ' (x) was ZERO.
"Two points where the average rate of change is...
Answer to:
A box contains 8 thick, 5 medium and 3 thin bolts. Another box contains 6nuts that fit the thick bolts, 4 that fit the medium bolts and 2 that fit the thin bolts. One bolt and nut are chosen at random. What is the probability that the nut fits the bolt?
There are 16 bolts and 12 nuts.
The number of ways of picking a bolt and a nut is 16*12.
Number of ways of picking a thick bolt and a thick nut is 8*6
Number of ways of picking a medium bolt and a medium nut is 5*4
Number of ways of picking a thin bolt and a thin nut is 3*2
Total number of ways of picking matching nuts: (8*6+5*4+3*2)
Probability of a match: (8*6+5*4+3*2)/(16*12)
...
Answer to:
How do I calculate the number of moles of Si3N4 produced from the 0.62 moles of N2 and 0.75 moles of Si?
For each mole of Si3N4 you need 3 moles of Si and 4 of N.
You are given 0.62 moles of N2 which is 1.24 moles of N.
and 0.75 moles of Si
0.75 moles of Si would be enough for 0.25 moles of Si3N4
1.24 moles of N would be enough for 0.31 moles of Si3N4
So you've got enough for 0.25 moles of Si3N4, which needs 1 mole of N, and then you have 0.24 moles of N or 0.12 moles of N2 left over.
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Answer to:
How is it possible for an infinite amount of rectangles, with areas of zero, to add to a sum?
This is misleading.
The "infinity" never actually happens, we never really get all the way there.
The integral is defined as a limit of a sum.
Limits are defined in such a way that the infinity never actually happens.
For instance, the limit of 1/(1+x) as x tends to infinity means informally the number that 1/(1+x) seems to "tend" to as x gets larger and larger....
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Answer to:
How do inductive mathematical proofs work?
You have a truth formula in terms of n, F(n)
You prove a base case for some specific value of n
For example, you prove the formula with n set to 4.
Then you prove an inductive step that for any given value of n, F(n) being true implies that F(n+1) is true.
Together this means that F(n) is true for all values of n greater or equal to 4.
In fact, it's a short hand for a very...
Answer to:
Can you prove the Law of Cosines using your own talents, not wikipedia
I'll have a go.
The cosine rule is:
a^2 = b^2 + c^2 - 2 b c cos A
Drop the perpendicular from A to side a.
This divides angle A into two angles: Say D and E.
The perpendicular has length h.
h = b cos D = c cos E
a = sqrt(b^2 - h^2) + sqrt(c^2 - h^2) from Pythagoras.
a^2 = b^2 + c^2 - 2 h^2 - 2 sqrt(b^2 - h^2) sqrt(c^2 - h^2)
a^2 = b^2 + c^2 - 2 h^2 - 2 b c (sin D) (sin E)
a^2...
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Answer to:
Can you teach me the hexadecimal system in a single answer?
1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,10,11,12,13,14,...,1E,1F,20, 21,...,99,9A,9B,9C,9D,9E,9F,A0,A1,...,FE,FF,100,101,...
The letters A-F stand for a digit with value 10 thru 15.
The hexadecimal number 10 is 16 in decimal.
The hexadecimal number 100 is 16*16 in decimal.
The hexadecimal number 1000 is 16*16*16 in decimal.
A hexadecimal number like 1BC means 1*16*16 + 11*16 + 12 where * is...
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Answer to:
A car acceleraes at 5 m/s quared. How much time does it take to reach 33 m/s?
33 divided by 5.
seconds.
Answer to:
Which contains more potato skins, 10 pounds of small potatoes or 10 pounds of large potatoes?
You get more smaller potatoes to the pound, so there are more potatoes and more skins.
If you're asking about "volume" or "mass" of skins, then it would depend on the relative thickness of the skins on small and large potatoes.
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Answer to:
Describe what happens to the surface area to volume ratio for larger and larger cubes. Predict if this pattern would also be observed for other geometric shapes such as a sphere. Explain the reasoning behind the prediction.
Surface area for a cube of side a: 6 a^2
Volume = a^3
ratio = a/6 which increases linearly with a.
This is observed for ALL geometric shapes.
If you multiply the size of the shape by k, then all lengths go up by a factor of k. In particular, the size of the sides on any square area on the surface of the shape will go up by a factor of k, and the area will go up by a factor of k*k.
...
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Answer to:
What is the probability, in a well-shufled deck, of finding a jack within one place of a 4 ( so you can have J-4 or J-(some other card)-4 )
J-4 is easier to calculate
The number of ways of shuffling the deck is 52-factorial.
But if you mustn't let a 4 arrive after a jack you have fewer combinations. There are 48-factorial ways of shuffling the pack except the fours.
There are 49 then possible positions for the four of hearts, but four of those follow a jack, so only 45 positions left.
Then there are 46 positions for the...
Answer to:
In a town where there are 4500 women, and you met someone named Linda, and then at a gathering of 20 there were 2 Linda's, what are the chances of 1 of those being the one you met?
In the 1940s, Linda was the eighth most popular name for a girl baby.
The probability of a girl baby being called Linda was 0.0156
If I assume this figure applies to the whole town in the question, then there are about 70 Lindas.
Your two Lindas who could have been any of the 70.
The probability of one of the Lindas being the one you met would be one in 35.
It's an interesting...
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Answer to:
1.124791105=(1+x)^3 I don't know the steps but i know the answer (6.7005%) Please help me
If
1.24791105 = the cube of (1+x)
Then
cube root(1.24791105) = 1+x
x = cbrt(1.24791105)-1
and to answer in percent, you need to multiply by 100%
How to find cube roots?
If you have logs and antilogs, take the log, divide by three, take the antilog.
Example: cbrt(x) = exp(ln(x)/3)
where exp(x) is the antilog of ln = e^x
EDIT: P.S. If the answer really is 6.7005% then...
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Answer to:
If you had an equation with say about 100 terms in it, would it possible to make one of them the subject of the equation ? if so how would you go about it?
move the one term onto one side by itself.
You do this by adding or subtracting the same quantity from both sides.
If you have a + x + b = c + 4x + d
subtract c and d from both sides:
a + x + b - c - d = 4x
subtract x from both sides:
a + b - c - d = 3x
Now divide to get x by itself:
(a + b - c - d)/3 = x
It is now the subject.
The equation acts like a two-pan balance....
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Answer to:
Find the resultant and difference of a vector with units 8 and moving in the direction N70E
The resultant is an old way of asking for the sum.
So you've been asked for the sum and difference of two vectors. And you've only given us one of them.
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Answer to:
"Solve the quadratic equation with complex coefficients. Write with z1 and z2 in 'a+bi' form. What is the relationship between the roots?' I. ix^2 - 3x + 4i = 0
You can use the quadartic formula for this.
(3 +/- sqrt(9 + 16)) / 2i
= 4/i and -1/i
= -4i and +i
Equations with real coefficients have roots which are complex conjugates.
I'm not sure what relationship is being saught here. The two roots are both purely imaginary.
Answer to:
How can an inductive proof (for all integers - you know, going from demonstrating n=1 works and then demonstrating k+1 works)... how can that be generalized to all real or complex numbers?
Positive real numbers:
Base case: Prove f(x) is true for 0<=x<=1
Induction step: Prove f(x+1) is true if f(x) is true.
There are analogues for complex numbers.
Example:
Base case: Prove f(z) is true for all complex numbers z with |z|<=1
Induction case: Prove f(z+k) is true if f(z) and f(k) are known to be true.
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Answer to:
How many multiples of 4 from 1-1000 do not contain any of the digits 6,7,8,9,0?
So how many multiples of 4 can be made from up to three digits from 1,2,3,4,5
1 digits: only 4.
2 digits: 12,24,32,44,52 (5 of them)
3 digits, same as 2 digits but with one of 1,2,3,4,5 on the front.
so there are 31 multiples of 4
Answer to:
The wheels on the car had a 30cm. radius and the car was traveling at 60km. per hour what was the angular velocity of the wheels in radians per minute
Circumference of wheel: (3/5) pi meters.
Travels: 60000 meters in an hour
= 1000 meters in a minute.
number of revolutions in a minute
1000 / ((3/5)pi)
Number of radians in a minute
2*pi * 1000 / ((3/5)pi)
2000 / (3/5)
3333 radians per minute.
Check: 3333 radians per minute = 200000 radians in an hour = 31828 revolutions in an hour. 1.885 meters per revolution. 0.6 meters diameter....
Answer to:
What is the difference between f(x)=1+ln x and f(x)=1+log x?
ln x
means the "natural" logarithm of x, which means the log to base e.
log x
means the logarithm of x. Hopefully the base is clear from context because it can sometimes mean base 10 and sometimes base e. Sometimes 'log' has a subscript which is the base.
Sometimes the log to base 10 of x is written log10(x) to make the base clearer.
Answer to:
In each second of fall, the distance a freely falling object will fall is?
In the first second, 16 feet.
In the second second, 48 feet.
In the third secdon, 80 feet.
In the nth second, (32n-16) feet.
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Answer to:
A pot falls from a ledge and hits the ground 45m below. The speed with which it hits the ground is what?
Well it would be about 66 mph if there was no air. In practice it'll probably be considerably less than that.
Answer to:
An 800 newton person is standing in an elevator. if the upward force of the elevator on the person is 600 Newtons, the person is:
a. at rest
b. accelerating upward
c. accelerating downward
d. moving downward at constant speed
600N isn't enough to support an 800N person... he's faaaaalllllliiiinnnngggggg! (with increasing speed)
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Answer to:
How can astronomical units be used to determine the time it takes for planets, in our system, to make one orbit around the sun?
Kepler's Third Law:
"The squares of the orbital periods of planets are directly proportional to the cubes of the axes of the orbits."
So if you know the distance of a planet to the Sun in AU (r) you can work out it's period (T) in years by T = sqrt(r^3)
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Answer to:
What is a panorama?And a panoramic picture?
A panorama is just a wide view.
A panoramic picture is just a wide picture showing more visual angle than you would normally see.
A 360 panoramic picture shows 360 degrees of view.
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Answer to:
How can scientists tell the temperature of the surface of distant bodies in space?
Hot things give off a distinctive spectrum. It's a hill shape. The hotter the object, the further up the spectrum the hill comes.
At first highest part of the hill is in the infrared, where we can't see that the object is hot by looking at it, because we don't see in infrared, but soon the hill starts to move into the red, and we say something is red hot.
Heat it up more,...
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Answer to:
Why is Pluto so far away
In a way, because our telescopes are so good.
As our telescopes got better and better we could see more and more planets.
Pluto was the furthest planet like object we could see for some time, but now we can see a lot more and futher, and so Pluto was has been demoted to a minor planet.
Answer to:
As the truck pulls the trailer up the ramp, the gravitational potential energy of the trailer is increasing. What force on the trailer is doing positive work to increase the potential energy of the trailer?
Er, the pulling force exerted by the truck on the trailer...
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Answer to:
A 5.4 kg bag of grocieries is in equilibrium on an incline of angle theta=15 degrees. Find the magnitude of the normal force on the bag.
5.4 times g times cos 15
where g is the gravitational acceleration.
Answer to:
If i have 2cos^2 x = cos^3 2x + cos^2 x can i divide by 2 and get cos^3 x + cos^2 x /2 on the left hand side?? and also if i have 1/2 cos 2x - notice not a square.. but just a 2x) would that in itself = cos x?
No, (1/2) cos (2x) is not the same as cos(x)
It might help to try this on a graph:
http://www.walterzorn.com/grapher/grapher_e.htm
(in the graph box, type (1/2)*cos(2*x);cos(x) instead of the formula that are there now)
If you have 2cos^2 x = cos^3 2x + cos^2 x and you want to solve for x, you have to change things like cos^3 2x
into powers of cos x
You can do that using tables...
Answer to:
Evaluate (2.002)^6 without a calculator
(2.002)^6 = (2 * 1.001)^6 = 2^6 * 1.001^6
2^6 is indeed 64.
But 1.001^6 is
1.006015020015006001
Each three digits from the right form the binomial coefficents 6Ci. 6C2 is (6*5)/(2*1)
Now to multiply by 64:
Multiply by 2:
2.012030040020012002
by 4:
4.024060080040024004
Add to get multiplication by 6
6.036090120060036006
And 60:
60.36090120060036006
+4.024060080040024004
...
Answer to:
Is there a term for the distance from the tangent point of a line with a circle to the intersection of this line with another line that is tangent to the same circle, if the two lines are not perpendicular? This concerns measuring a machi
The line you describe is also called the tangent.
This is a less well known meaning of the word: A line tangent to a circle which means an extended diamater.
The length is calculated as "r tan t"
where r is the radius of the circle and t is the angle between the line joining the center to the tangent point and the line joining the center to the intersection point.
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Answer to:
A box has 24 marbles. There are 3 colors of marbles and 8 of each color. A sample of two marbles is chosen from the box. What is the probability the two marbles are the same color?
Ways of picking two marbles at random from 24: 24C2
Ways of picking two of the same color from 8: 3*8C2
24C2 is a binomial coefficient calculated as (24*23)/(2*1)
(3*(8*7)/(2*1)) / ((24*23)/(2*1))
=3*(8*7) / (24*23)
= 7 / 23
Answer to:
Given:line AE is tangent of point B.line BC =5 and line AE =24. What is measure of line EC
The word tangent, is usually used of circles, and your question is impossible to solve as it is. Is there a circle somewhere?
All you can say from the information given is that EC is less than 29.
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Answer to:
How do you find the derivative of a function expressed as an integral when the 2nd value of the interval is x^2 as opposed to simply x?
Nice one.
So you have something like:
g(x) = integral t=0..x^2 of f(t) dt for some formula f(t)
and you want to find the derivative wrt x.
Suppose you could integrate f(t) wrt t indefinitely and get a new formula F(t)
Then, by definition, the definite integral is F(b) - F(a) where a and b are the two limits.
So now you have g(x) = F(x^2) - F(0)
You can now find the...
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Answer to:
Derive the quadratic formula from a quadratic in the form: cx^2+ax+t
cx^2 + ax + t = 0
x^2 + (a/c) x + (t/c) = 0
x^2 + (a/c) x = - (t/c)
The left side is nearly square.
it's NEARLY equal to (x + (a/2c))^2 just missing a (a/2c)^2
So "complete the square" by adding (a/2c)^2 to both sides.
x^2 + (a/c) x + (a/2c)^2 = (a/2c)^2 - (t/c)
(x + (a/2c))^2 = (a/2c)^2 - (t/c)
x + (a/2c) = +/- sqrt((a/2c)^2 - (t/c))
x = - (a/2c) +/- sqrt((a/2c)^2 -...
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Answer to:
What is the evaluated answer for "3R squared + (2R) (R)"? i mean i understand how it would end up being "5R squared" but where did the "2R squared" come from? like, can you explain how "(2R)(R)" becomes "2R squared"? wouldnt it be like 3R squared?
(2R)(R) means (2 times R) times R
"R squared" means R times R
(2R)(R)
= (2 times R) times R
= 2 times (R times R)
= 2 (R squared)
ok?
Answer to:
Calculate the energy in a photon (quantum) of blue light when the frequenzy of the blue light is 1 x 10^15 Hz.
E = h v
where E is energy, v is frequency and h is
Planck's constant: h = 6.62606896 x 10^-34 J s
All you have to do is add 15 to the -34 and remove the s.
(because Hz means 1/s)
Answer to:
Help to find the slope in a line. -y=-3x+5
The equation is y = mx + c
m is the slope
You need to get y alone on one side of the equation.
When you've done that, the coefficient of x is the slope.
Answer to:
A series of experiments are carried out on a hoisting provide the formula E=aL+b where L=load and E=effort required to raise it. 2 of the experiments used to obtain the formula were: E=10 L=24 and E=14 and L=90. Whats the values of a and b from data.
E=aL+b ... it's a linear equation.
Just like
y = mx + c
The slope m is given by
m = increase in y / increase in x.
a = increase in E / increase in L.
a = 4/66
Substitute one of your examples to find b.
Answer to:
I need this answer ASAP! Decide whether the lines are parallel, perpendicular or neither? 2x+2y=4 and 6x=6-4y.
In these eqations:
ax + by = ?
cx + dy = ?
If a/b = c/d the lines are parallel.
if a*c+b*d = 0, the lines are perpendicular.
So put your equations in that form first.
Answer to:
How many 3-digit positive integers are odd and do not contain the digit “5”? and how would i find that out in a simple and fast way?
8 possibilities for the first digit (can't use 0 or 5)
9 for the second digit.
4 for the third: 1,3,7,9
Answer: 8 times 9 times 4
Answer to:
1. Solve for x: 3log6(x)=log6(8) 2. Solve for x: 2ln(x-3)=ln(15-x)
1 3log6(x)=log6(8)
First change the left side: 3log6(x) = log6(x^3)
because arithmetic on logs is like arithmetic on powers:
a^(b*3) = (a^b)^3
Now you have log6(something) = log6(something)
so the somethings must be equal.
2. Solve for x: 2ln(x-3)=ln(15-x)
Same idea:
change 2 ln(x-3)
into ln( (x-3)^2 )
Answer to:
Mar rides rides her bike to Jon's house and returns on the same route. Mar rides her bike @ constant speed of 9mph on level ground, 6mph going uphill, 18mph goiing downhill. If her total time riding is 1hr., how far is it to Jon's house?
The only way this can have a definite answer is if travelling 6mph up a hill and 18mph down that hill is the same as travelling 9 mph there and back on the level. If this is not true, then you'd need to know how much hill there was on the way to Jon's house.
So test it: Over 18 miles, up and down hill is 3 hrs up, 1 hr down = 4 hours.
18 miles level is 2 hrs there, 2 hours back...
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Answer to:
A cone has an altitude of 15cm and a radius of 3cm. A right circular cylinder of radius r and height h, is inscribed in the cone. Write h as a function of r.
when h = 15, r = 0
when h = 0, r = 3
these are two points through which you must fit a line.
The slope is -5 of h for each unit of r: use the standard slope equation: difference in height divided by difference along: (0-15)/(3-0)
so h = something - 5r
h = 15 - 5r
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Answer to:
A standard 6-sided die's probabilities of rolling 2,3,4,5,or 6 are equal and the probability of rolling 1 is twice the probability of rolling a 2. If the die is thrown twice, what is the probability that the sum of the numbers thrown will be 4?
That's not a standard six sided die!
Pretend there are seven sides and two of the sides are labelled 1a and 1b. That would satisfy the question.
Two such dice, the number of ways of making four is:
1a + 3
1b + 3
2 + 2
3 + 1a
3 + 1b
five ways of making 4 and 7*7 possibilities altogether = 5/(7*7)
Answer to:
65.4% of the population is male. 18.9% of the male population and 34% of the female population are under the age of 15. What percentage of the total population is under 15?
100-65.4 = 34.6% are female
Easiest to convert to proportions by dividing by 100% first:
0.654 male, 0.346 female
need
0.189 of 0.654 and 0.34 of 0.346
Answer as a proportion:
(0.189*0.654 + 0.34*0.346)
Answer as a percentage, just multiply by 100%:
(0.189*0.654 + 0.34*0.346)*100%
Answer to:
If all of the digits must be different, how many 3-digit odd nmbers greater than 700 can be written using only the digits 1, 2, 3, 5, 6, and 7?
The trick to this is noticing that to make a three digit number greater than 700 with those digits you'll have to start it with 7 (one possibility).
The last digit can only be 1, 3 or 5 (three possiblities).
and the middle digit can be any of the four remaining digits, as we started with six digits and used two. (four possibilties)
Total possibilities = 1 times 4 times 3 = 12.
...
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Answer to:
Tom has 9 more baseball cards than Ken and Jill has 3 less than Randy. If Randy has 4 more cards than Ken, could the total number of cards they have be 45?
Take 9 cards off Tom. Now Tom and Ken have the same.
Take 4 cards off Randy, now Randy and Ken have the same.
Randy now has one less than Jill.
Take 1 card off Jill. Now Jill and Ken have the same too.
So Ken Tom Randy and Jill now have x each.
4x + the 14 cards I took away = 45?
4x = 31
x = 7.75 so, no not really.
Check:
Tom has 16.75
Ken has 7.75
Randy has 11.75
Jill has 8.75...
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Answer to:
This is from my calculus class. I need to find the first and second derivative:
M(x)=(x+2)ln(x) for 1 <_ x <_ 3 (<_ means less than or equal to)
I came up with M'(x)=2+ln(x) but it was wrong. :(
Derivative of a product (u v) ' = u ' v + u v '
That's ln(x) + (x+2) ((ln(x)) ')
So what's (ln(x)) ' ?
This is not something you can easily work out.
You may know you can do it like this:
Let y = ln (x)
so e^y = x
derive both sides wrt x:
e^y (y ') = 1
y ' = 1 / e^y
(ln(x)) ' = 1 / x
so the result you should have got was...
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Answer to:
What is defination of infinity?
infinity has a number of different definitions depending on what the context is.
Take this:
"The limit as x tends to infinity of 1/x is 0."
This kind of infinity is just shorthand for "increases without bound"
The long hand version is:
"If you give me any small number epsilon, then I can find a number N such that the distance of 1/x from zero is less than...
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Answer to:
Spring function from my calculus class. This doesn't make sense to me!
Consider the function p(t) = (cos(2*pi*t)/(T)) where T is a constant. Consider a spring with k=1.0 and m=5.0. Find the period T that produces a solution of the spring equation.
The force exerted by the spring is given by
F = -k x (this is the spring equation)
The acceleration this produces in the mass is
a = -k x/m (using F = ma)
but a, the acceleration, is the second derivative of x wrt t
so
x ' ' = - k x/m
where ' denotes the derivative wrt t.
You've been told that x=p(t) might be a solution of this equation. So...
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Answer to:
If 5f(x)+f(5-x)=x^2 What is f(x)?
A solution is
f(x) = (4 x^2 + 10 x - 25)/24
I found that by swapping f(x) and f(5-x):
If 5f(x) + f(5-x) = x^2 then by symmetry:
5f(5-x) + f(x) = (5-x)^2
That's two simultaneous equations in two "unknowns".
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Answer to:
What causes short Gamma Ray bursts?
Supernovas, big things dropping into black holes, black hole collisions? But GRB's are still being studied to find the answer to that question.
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Answer to:
I'm trying to come up with a simple formula to work out my Alcohol volumes after mixing.... Any help would be appreciated!..... Example: I have 800ml of 40% Alcohol, I then make that up to 1125ml with water. What is the new alcohol percentage content?
40% alcohol is literally 40% alcohol.
So 800ml of 40% alcohol is 800 * 40/100 = 320ml of alcohol.
Afer you've made it up to 1125, you've got a proportion of alcohol of 320/1125. Multiply that by 100% for a percentage.
Answer to:
How many inches is 15 mm
75/127 (seventy-five one-hundred-and-twenty-sevenths) of an inch.
Answer to:
What is the point of concurrency used to circumscribe a circle for a triangle?
The circumcenter. It is at the intersection of the perpendicular bisectors of the sides.
Answer to:
What is the point of concurrency used to inscribe a circle for a triangle?
The 'incenter' of the triangle.
It is at the intersection of the angle bisectors.
Answer to:
In a bombing attack there is a 50% chance that a bomb strikes a target .Two direct hits are required to destroy a bridge completely .How many bombs must be dropped to give a 99% chance or better to completely to destroy the target
Drop n bombs.
Now it is a binomial distribution.
The chance of i bombs hitting is nCi p^i q^(n-i)
here p=q=50% so it simplifies to nCi/2^n
So chance of 0 bombs hitting is nC0/2^n = 1/2^n
Chance of 1 boms hitting is nC1/2^n = n/2^n
Chance of zero OR one bomb hitting = (n+1)/2^n
You want (n+1)/2^n <= 0.01
n=1 gives 1 = 100% chance of failure
n=2 gives 3/4
n=3 gives 4/8 =...
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Answer to:
Does a zero with a slash through it mean something different in math then just a zero?
Yes, a zero with a slash through it can also mean the empty set, the set of no items.
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Answer to:
The radius of a circle is modeled by the function r(t)=3t, where t is the time in minutes and r is measured in meters. Write a function for the area directly as a function of t by computing (A*r)(t)
I'm not sure what you mean by (A*r)(t), especially as you haven't mentioned A.
But the area of a circle is pi r^2
and if r is 3t
then it is
pi (3t)^2 = 9 pi t^2
- which is a function of t.
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Answer to:
In 10000 tosses of a coin how many times will 6 consecutive heads be expected to occur? What is the general formula to work this out for "N" tosses and "X" consecutive heads?
In six coin tosses, you expect 6 consecutive heads with a probability of (1/2)^6
There are N-X+1 positions in which these consecutive heads can occur.
Approximately, these events are indpendent, so you have a binomial distribution where n=N-X+1 and p=(1/2)^X whose mean is np = (N-X+1) (1/2)^X
This will work well if X is much smaller than N.
But in practice the events "six heads...
Answer to:
F(x)= (2x^4)/8 + (x^12)/6 how can i derive this?
I assume you mean 'derive' in the sense of 'differentiate'
You use the differentiation rules:
If D(P) means differentiation of P with respect to x,
then
D(A + B) = D(A) + D(B)
D(A) D(B) = A D(B) + D(A) B
D(K) = 0 where K has no x
D(x) = 1
D(A / B) = (A D(B) - D(A) B) / B^2
D(A^n) = n A^(n-1) D(A)
You jsut apply these rules mechanically until there are no...
Answer to:
If f is a differentiable function such that f(9) equals 2 and f ' (9) equals negative 2, what is the linearization?
The Taylor expansion of a function about a is:
f(x) = f(a) + (x-a) f '(a) + (x-a)^2/2! f ''(a) + ...
I expect you want just the first two terms of that sum.
(where a=9)
Answer to:
If the odds in favor of the Rangers winning the game are 7 to 5, what is the probabiltiy that they will win?
7 to 5 means 7 chances of winning vs 5 chances of losing.
That's 12 chances altogether, and the probability of an event P(event) is number of equally likely outcomes in which event happens divided by total number of equally likely events = 7/12
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Answer to:
There were seven nominees for president and four nominees for vice president. In how many ways can the slate be chosen?
28 provided that there are 11 people in the question (no duplicates).
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Answer to:
A committee of three is selected at random from a set consisting of five democrates, eight Republicans, and two Independents. What is the probabiltiy that the committee consists of no Republicans?
Number of ways of choosing three from 15 is
"15 choose 3" or 15C3 and it is calculated as (15*14*13)/(3*2*1)
Number of ways of picking no Republicans is 7C3.
The probability is 7C3/15C3
the denominators (3*2*1) will cancel leaving you with
(7*6*5)/(15*14*13)
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Answer to:
Which of the following statements is a tautology?
Integers are rational numbers.
Whole numbers are natural numbers.
Rational numbers are irrational.
Irrational numbers are integers.
Counting numbers are 1,2,3,4,5,...
Integers are the numbers 0,1,-1,2,-2,3,-3,...
"whole numbers" isn't well defined. It can mean counting numbers or it can mean integers.
Natural numbers are positive integers: 1,2,3,4,5,...
or sometimes non-negative integers: 0,1,2,3,4,5,...
Rational numbers are any numbers that can be expressed as a ratio of any two integers: 1/2,...
Answer to:
What is the sun made of?
Hydrogen and Helium gas and plasma.
Altogether now...
"Ohhhhhhh, the Sun is a mass of incandescent gas ... "
http://www.youtube.com/watch?v=Oyz7e8iQ6Uo&feature=related
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Answer to:
How do you calculate the capacity (in liters and gallons) of an aquarium based on it's volume?
If you have an aquarium which is a rectangular prism shape, then height times length times breadth gives volume in cubic length units.
Then you just convert using the appropriate conversion.
These should be enough:
1 cubic metre = 1000 litres.
1 US gallon is 3.785411784 liters.
1 US gallon is 231 cubic inches.
1 cubic metre is 1000000 cubic centimeters.
1 cubic foot is 1728 cubic...
Answer to:
Write and solve.
andre hit four more home runs than twice the number of home runs larry hit. together they hit 10 home runs. how many home runs did andre hit?
Larry didn't do very well.
after subtracting four runs from andre's total, he still only scored half as much.
Larry = half of (andre-4)
together they hit 10 home runs:
andre + larry = 10
andre + half of (andre-4) = 10
half of (andre - 4) = 10 - andre
andre - 4 = 20 - (twice andre)
(three times andre) = 20 + 4
andre = 8
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Answer to:
GAAAAAAAAH Can someone help me with this problem!?!? I've been staring at it for 20 minutes :( If you're going to answer, please go step by step, I can't figure out where I went wrong.... :( I'll post my process and answer in answer
Using matrices:
4x - 5y = 13
2x - 7y = 24
(4 -5)(x) = (13)
(2 -7)(y) = (24)
(a b)
(c d)
goes to
(d -b)
(-c a)
divided by (ad-bc)
So
(x) = (-7 5) (13) divided by -18
(y) = (-2 4) (24) divided by -18
x = -7*13+5*24 divided by -18
y = -2*13+4*24 divided by -18
x=-29/18
y=-70/18
Sorry, the formatting has messed up your answer and I can't see where you went...
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Answer to:
When driving, the road exerts a forward force on the tires of your car, according to newton's third law of motion, what would be the reaction to this force
If A exerts a force on B, the reaction force is the force exerted by B on A.
So here, if the road exerts a forward force on the tires of your car, your car exerts a backward force on the road.
If the car was on a platform on wheels, you'd see you'd see the platform move back as the car tried to move forwards.
Answer to:
In the double helix shape of DNA, what series of nucleotides would match the nucliotide series G-A-C-T? A. A-G-T-C B. C-T-G-A C. T-C-A-G D. A-C-G-A
AGTC
BUT it's a bit of a trick question.
It's C pairs with G and T pairs with A, so it would be CTGA seen from this side, but seen from it's own side, it goes the other way...
Answer to:
What is the longest side in an obtuse triangle?
The side opposite the obtuse angle.
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Answer to:
How many pound coins would fit in a swimming pool with a depth of 2 metres a width of 12 metres and length of 25 metres?
Diameter: 22.5mm
Thickness: 3.15mm
stolen straight from wikipedia.
Now the rest is hard. What's the mathematically best way to pack pound coins into a swmiming pool to get the most in? The answer is, I believe, no one knows.
Suppose we do it in layers. There will be 634 layers and not quite enough to get another in.
How many on each layer?
I imagine a pattern where there is a 25m...
Answer to:
If a surveyor is standing 50 feet away from the base of a tree and measures his angle of elevation to the top of the tree to be 71.5 degrees, how accurate must his measure of the angle be to get the height of the tree within 6% accuracy.
That's a good one, I've not heard one like that.
Assume the surveyor was wrong. We assume he is too low by some small angle theta. (same as too high by an angle -theta)
Now we find the correct height, H, of the tree using the angle (71.5+theta) degrees.
The surveyor's actual calculations using 71.5 degrees gives another value for the height: h.
The surveyor's value h...
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Answer to:
What is the equation to convert volume to grams?
mass = volume * density
where each is in matching units.
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Answer to:
What is f(x) if f(x) = {x for x<_ 6, / {6 for x > 6? The difference quotient, An indeterminate function, A picewise function, or a step function.
That's a piecewise function, (not a picewise function), because it is defined in two pieces.
Good try with the notation! '<_' is written '<=' in text form, meaning 'less than or equal'
Answer to:
What is this: f(x+h)-f(x)? difference quotient, denominator quotient, numerator of the difference quotient, just an algebraic expression.
It appears that ((f(x+h) - f(x))/h) is called the 'difference quotient'.
So f(x+h)-f(x) is the numerator and h is the denominator.
The odd thing is, I've never heard this name before. It would be interesting to know whether it is *really* due to Newton or is some modern invention.
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Answer to:
Find and simplify the difference quuotient f(x+h)-f(x) over h, h=/ 0 for the given function. f(x) = 3x-9.. a. 3+6(x-9) over h, b. 0, c.3, d. 3+ -18 over h
f(x) = 3 x - 9
f(3) = 3 threes - 9
f(999) = 3 999s - 9
f(orange) = 3 oranges - 9
f(x+h) = 3 (x+h) - 9 = 3x + 3h - 9
Just subtract f(x) from f(x+h) and then divide by h
Answer to:
HELP! QUIZ QUESTION! give the exact coordinates of the extreme points of the cubic f(x)= (3x^3)-x+2
You wanted to know how to do it:
The extreme points occur when the derivative is zero.
differentiate f(x) to make f '(x), the derivative.
Solve f '(x) = 0 to get two values of x.
Substitute those two values into f(x) to get the y coordinates.
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Answer to:
What is a solution and how can you tell how many solutions you have on a set graph?
An equation is something like:
x + 2 = y + 4
A solution is a set of matching values for the variables which makes this equation true. For instance, in my example, y=2 and x=4.
An equation of two variables can be be plotted on an xy graph. Most are curves or lines. Every point on the curve or line corresponds to a possible solution to the equation.
If you have more than one equation,...
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Answer to:
What are the odds of surviving this particular car crash: Subject is a 21 y.o. male, driving a PT Cruiser @ about 60-65mph. fell asleep, woke in time to turn away from pit/medianVeihicle flipped end over end once, rolled 3x. The car was totaled
There are many factors that come into play.
Is the driver secured (I assume a seat belt)?
Was the space inside the car occupied by the driver significantly distorted - probably not, cars have safety cages - a 'totalled' car does not mean it was crushed flat.
What decceleration was the car and occupant put under - the fact that the car flipped and rolled means that the kinetic...
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Answer to:
Ok, I have a basic understanding of how to do these, sorta, but I need someone to walk me through how do do EACH of these promblems.
OK the first:
1.
(x-1)(x+2)(x-4)(5x-6) > 0
2.
(x-1)^3(2x+3)(x-5) < 0
3.
(x-10)^2(x+6)(3x-9)(2x+12) > 0
One way to do these would be to sketch the graph of (x-1),(x+2),(x-4),(5x-6). you can easily see when each bracket is positive or negative on the graph, so you can see which areas of the number line would have a positive product of four values and which a negative product.
The first bracket is a line of slope 1 which passes through zero when x is 1
This is not only as easy as doing it...
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Answer to:
1.(a) the percentage impurity of a chemical can be modelled by a normal distribution with a mean of 5.8 and standard dev of 0.5. Obtain the probability that a sample of the chemical has percentage impurity between 5 and 6.
Ok, ok, this one is slightly different to the other ones.
Once again, map to standard normal distribution.
5 is 0.8 below 5.8. Divide 0.8 by 0.5 to find that 0.8 is 1.6 standard devations. So 5 is 1.6 standard deviations below the mean. (-1.6)
and 6 is 0.4 standard deviations above the mean (+0.4)
So you have to find the area under the standard normal distribution curve between -1.6...
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Answer to:
I have a pdf of f(x) = {(3/2)*(1/x^2) for 1<= x <= 3 or 0 otherwise I need to find the cdf.... I know that cdf is defined as F(x)= integral( f(y) dy) from negative infinity to x, where f(y) is the pdf. keep getting 1 as an answer... dont think its right
The cdf F(x) is the area under the pdf graph up to x.
f is zero to the left of x=1, so F(x) is zero too.
It all starts at x=1
The area between x=1 and x=T is
Integral x=1 to T of f(x) dx
which is a definite integral with limits.
You do the integration to get a function, g(x) say.
Then you find
F(T) = g(T)-g(1) which will be a formula of T.
Answer to:
How do you determine cdf from a piecewise pdf?
You have to find the area to the left of x.
That means finding the area under each piece of the pdf.
Answer to:
In summer the daylight hours are shorter/longer.
Do you live on the equator? How can you not know the answer to that?
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Answer to:
What WAS the purpous of our tailbone?
You'll kick yourself...
...
...
...
It used to be part of a tail.
:D
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Answer to:
How much does a tennis ball compress on a bounce when dropped from a height of 75 centimeters with initial velocity=0?
Well I could if you could tell me the Young's modulus of your tennis ball, the coefficient of elasticity.
It varies from ball to ball, and is higher with new balls.
Answer to:
1.(a) Describe 2 of the main features of the shape of a normal distribution?
It's symmetric about the center.
The highest point is in the center and it slopes away towards zero each side.
It's continuous - so the top of the hill is not pointy.
The graph never quite hits zero on either side.
The area under the graph is 1.
It looks like a hat.
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Answer to:
The time, X minutes taken by Fred Fast to install a satellite dish may be assumed to be a normal random variablewith mean 134 and standard deviation 16. (i) Determine P(X<150). (ii) determine, to 1dp, the time exceeded by 10% of installation.
These are all the same - you map to the standard normal distribution and map back.
i)
If the mean is 134 and standard deviation is 16, then
P(X<150) is P(X<(1.00 standard deviation above the mean))
You have to look up that on a standard normal distribution table.
ii)
Look up what number of standard deviations above the mean corresponds to 90% of the measurements on a standard...
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Answer to:
The weights of hens' eggs are normally distributed with a mean of 65 grams and a standard deviation of 10 grams. Eggs whose weights are less than 56.5 grams are classified as small. A) calculate the porpotion of eggs classified as small.
You can't really calculate that.
You know that eggs whose weights are less than 56.5 g are small.
That's (65-56.5)/10 standard deviations below the mean.
Which is 0.85 standard deviations below the mean.
But to know what proportion that comes out to, you need to look up -0.85 on a table which shows the area under the standard normal distribution curve.
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Answer to:
A box contains 4 white, and 3 red marbles. Two marbles are randomly chosen without replacement. Find the P(White|Red).
Do you mean "find P(Second marble White | First marble Red)" ?
| means "given".
So take the "first marble red" event as having already occurred.
Now there are 4 white and 2 red left.
Probability of "second marble white" given "first marble red" is now 4/6 = 2/3
Answer to:
What is a kind of acid with 3 elements? the answer is a seven letter word, beginning with "o"
Another answer you might be looking for is 'oxyacid'
which is any acid which has Hydrogen, Oxygen and one other element, such as Nitric, or Sulfuric acids.
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Answer to:
Suppose that the sample size n= 25, the sample standard deviation is s=5, and the sample mean is 75. The 95% confidence interval for the population extends from about: a) 70 to 80 b) 50 to 100 c) 25 to 125 or d) 73 to 77.
68% of the population lie within one standard deviation either side of the mean.
95% of the population lie within about two standard deviations of the mean.
I make it 65.2 to 84.8 which really doesn't match any of those answers. ???
But then confidence intervals are not normally applied directly to a population, but to a hypothesis.
Perhaps some of the question is missing.
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