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A label to cover a plastic cup |
2012-10-23 |
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Kevin pose la question : I'm trying to make a label to cover the entire outer area or a plastic cup. I know there must be a way to figure out the dimensions needed, but I can't seem to figure it out. The circumference of the bottom of the cup is 21.4cm and the circumference at the top of the cup is 29.8cm. The cup is 14.5cm tall. What should the height of the arc from the plane connecting the two ends of the 21.4cm arc. I attached a diagram where x is the value I'm looking for. I'm guessing there is some simple relationship between the length of a line and the arc needed to turn that line into a perfect circle, but I don't know what it is. Can you figure this out and share it with me? Thanks.
-Kevin Penny Nom lui répond. |
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Differentiation rules |
2012-10-23 |
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Morgan pose la question : Use the derivative rules to differentiate each of the following:
1. f(x)=1/x-1 2. f(x)= sqrt(x) Penny Nom lui répond. |
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Some 6 digit numbers |
2012-10-23 |
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Mason pose la question : How many different 6 digit numbers can you make using the digits 1 ,2 5, 6, 7, and 9? How many of these six-digit numbers are divisible by 6? Penny Nom lui répond. |
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A 2 acre plot |
2012-10-22 |
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bob pose la question : If a plot of land on the south side is 290.16 feet wide, how many feet on the west and east side to the north to make a 2 acre plot?
Thank You Bob Penny Nom lui répond. |
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Two swimmers |
2012-10-22 |
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Emily pose la question : Two swimmers start from opposite sides of the pool. Each swimmer swims the length of the pool and back at a constant rate. They pass each other for the first time 40 feet from one side of the pool and for the second time 45 feet from the other side of the pool. What is the length of the pool? Penny Nom lui répond. |
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Solving for a/b |
2012-10-21 |
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Jenny pose la question : If a + 3b is equal to 175% of 6b, what is the value of a/b? Penny Nom lui répond. |
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Converting a fraction to a decimal |
2012-10-20 |
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A Teacher pose la question : My students want an easy way to convert a fraction to a decimal, can I get one from you? Penny Nom lui répond. |
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Two congruent circles in a rectangle |
2012-10-20 |
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Alexander pose la question : Have you ever solved a problem, in which you have a rectangle, from which you need to cut the largest two circles of equivalent diameter? I bisected a rectangle diagonally, but the circles, while tangent to two of the sides, are not tangent to eachother. Can you devise a method for two equivalent circles, that are tangent to two sides, are also to eachother?
Take for example a piece of paper, Each if the two largest circles has a diameter that is greater than the distance to the midpoint of the diagonal bisector of the rectangle. Chris Fisher lui répond. |
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A proof by contraposition |
2012-10-19 |
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Rahul pose la question : I am not able to understand the following,
To prove that if for all e>0, |x|0, then |x|>=e. I understand the approach very well but I do not understand why if |x|=e then |x|>=e. If it is so then why not |x|=
Thanks in advance!'
Rahul. Penny Nom lui répond. |
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A function with 3 asymptotes |
2012-10-19 |
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rimoshika pose la question : find a function that have 3 Asymptotic : y=x/y=sinx/x=-1 Penny Nom lui répond. |
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Whites and Sulphurs butterflies |
2012-10-19 |
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Arlene pose la question : The Whites and Sulphurs are one major family of butterflies. There are about 720 varieties. Eleven times more Whites and Sulphurs live outside North America, mostly tropical Asia and Africa, than live inside North America. How many of this family of butterflies live in North America? How many live in the rest of the world? Penny Nom lui répond. |
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The nth term of a sequence |
2012-10-19 |
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Emily pose la question : I don't understand how to do this question:
Nth term for 9, 7, 5, 3, 1
Is there a fast way to do nth term for this question? Or in fact any question? Penny Nom lui répond. |
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Revolutions per second |
2012-10-18 |
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Crystal pose la question : Suppose a car wheel is 26 inches in diameter.
a) If the tire completes one rotation, how far would the car travel?
b) If the car is traveling at 60 miles per hour, how fast is the car wheel spinning in revolutions per second? Penny Nom lui répond. |
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Passing out graph paper |
2012-10-18 |
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Andrea pose la question : mr karnowski has a stack of 125 sheets of graph paper.He is passing out g sheets to each of his students. What is the expression for the number of sheets he will pass out to the first 5 students? Penny Nom lui répond. |
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Percentiles |
2012-10-17 |
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Kenneth pose la question : Question from Kenneth:
Hello:
What is a common calculation used to determine percentiles?
For example, five employees have the following salaries:
Office worker 1 - $25,000
Office worker 2 - $27,000
Office worker 3 - $30,000
Office worker 4 - $32,000
Office worker 5 - $35,000
What is the percentile rank of office worker 3 who earns $30,000?
Here's what I know: Add the number of salaries. Total: 5
Add the smallest number of salaries less than $30,000. There are two.
Now, divide 2 by 5 and multiply by 100. 2/5 * 100 = 40
I think the office worker making $30,000 is in the 40th percentile.
and I'm not sure what this ranking indicates.
I thank you for any helpful reply and or different calculation. Harley Weston lui répond. |
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