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Solving an equation for D |
2008-12-18 |
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From Darrin:
In his finance class, my son is being asked to take the following equation and solve for "D":
1 / [1 - (1 + D/12)^T] = (1 / D) * [((12*B) / (P*T)) + Y + ((12N * Z) / (360T))] - [(12Z) / (360T)] * F
Answered by Robert Dawson. |
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The volume of a feed hopper |
2008-12-18 |
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From John:
I need to calculate the volume of a feed hopper, and I'm not sure how to break it down. The top of the hopper is 36" x 36", it is 30" deep, and ends at a 6" x 6" plate. One side of the hopper is straight top to bottom, of course tapering on two sides to meet at the plate. The other three sides angle down at about 75 degrees. I need to determine the cubic foot volume of this hopper (it is used for ground coffee) so I can configure a vibrator to knock down residual grounds. Thanks.
Answered by Robert Dawson. |
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Integral of cos^2 X between pi/2 and 0 |
2008-12-18 |
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From Wanda:
Integral or Area of cos^2 X between pi/2 and 0.
The answer that I got is -pi/4. Is this correct? If not, how did you come up with your answer?
Answered by Robert Dawson. |
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The inverse function for F(x)=x^3+x |
2008-12-18 |
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From alireza:
I want inverse function for F(x)=x^3+x
Answered by Robert Dawson. |
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The 2 rightmost digits |
2008-12-18 |
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From Peter:
Is there a pattern for the 2 rightmost digits of a power? For example, one problem for a math competition was what are the 2 rightmost digits of 3^1993?
Answered by Robert Dawson and Victoria West. |
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Coefficient of variation |
2008-12-17 |
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From JR:
I have read your reponses regarding the coeffcient of variation (CV) and find them very useful. I still have a question about interpreting the CV. Let's that the CV of sample #1 is 3% and that of sample #2 is 12%. Can I report that Sample #2 is 4 times more variable than sample #1? Thanks in advance!
Answered by Robert Dawson. |
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The angle between two lines |
2008-12-17 |
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From abhi:
how to calculate the angle between two lines, given the length of the lines..
angle should vary from 0 - 360 in the counterclockwise direction
Answered by Robert Dawson and Harley Weston. |
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An equilateral triangle |
2008-12-17 |
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From lorraine:
an equilateral triangle has side lenghts of10.the length of its altitude is?
Answered by Penny. |
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Solve for x |
2008-12-16 |
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From Melissa:
I have a test tomorrow and I'm hoping you can help me before then. I can never seem to solve the "RESOLVE X" problems, or in french resous pour x/
They look like this. 3x+2\6=2x-5\3. I only understand NOTHING from that.
Another equation is 2(x+1)=3(x+2).
Answered by Robert Dawson and Penny Nom. |
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What is a group of three numbers within a larger number? |
2008-12-16 |
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From kim:
My daughter brought home a question for math homework. What is a group of three numbers within a larger number?
Answered by Robert Dawson and Harley Weston. |
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Order from least to greatest |
2008-12-16 |
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From staci:
order from least to greatest on a number line,
7/10
3/5
5/10
Answered by Robert Dawson. |
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Two numbers |
2008-12-15 |
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From HERB:
I am thinking of two whole numbers. When I add them , their sum is 123. When I subtract the lesser number from the greater number their difference is 45. What are my numbers?
Answered by Penny Nom. |
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Why is the difference between british and american counting? |
2008-12-15 |
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From Muhammad:
Why is the difference between british and american counting?
Example 1 Billion american = 1,000,000,000 but,
1 Billion British = 1,000,000,000,000
Answered by Robert Dawson and Harley Weston. |
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The middle term of an arithmetic sequence |
2008-12-15 |
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From Leigh:
Find the sum of the first fifteen terms of an arithmetic series if the middle term is 92
Answered by Penny Nom. |
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Surface area of an irregular shape |
2008-12-15 |
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From Patrick:
An irregular shaped object (lets say a gold nugget, not smooth with
pockets) can have its volume determined by comparing its mass in
water.
Is there any method or means or anything that could be used to
determine the surface area of this shape? Whether that be theoretical
mathematical formula to using a special infrared technique,etc...
The problem I foresee is that the component parts cannot be divided
into smaller geometric shapes. I would propose an answer although I
don't know if it is a good one: A liquid material that dries super-thin, but
has a very specific and easily determined volume/mass is coated over
the object. Measure the mass difference between the beginning sample
of fluid and the mass after the object has been coated. Then determine
the surface area of the same mass of fluid in a geometric shape.
Is this feasible?
Answered by Robert Dawson. |
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