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Increasing the weight |
2000-03-23 |
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From Lee Millard:
A weight of dimension a, b is to have its weight increased by w% by bolting plates of the same material along the top and one side (but not at both ends). The top plate and side plate have the thickness, x. Find the thickness of the plates for a given weight increase of w%.
Answered by Penny Nom. |
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Sylvester's Problem |
2000-03-23 |
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From Sheryl Webb:
I am trying to find a proof of the theorem: Given n points in a plane, there is a line that contains exactly two points.
Answered by Chris Fisher. |
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A parabola problem |
2000-03-23 |
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From Morin:
I need to prove that if parabola x2=4py has a chord (not necessarily a focal chord) intersecting it at points A and B, with tangents to the parabola at points A and B that intersect at C, then a line drawn through C and the midpoint of the chord M is parallel to the y-axis. Further, prove that the point D where this line intersects the parabola is the midpoint of line CM.
Answered by Penny Nom. |
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Reflex angles |
2000-03-22 |
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From D. Reed:
What is the name of an angle that exceeds 180 degrees?
Answered by Penny Nom. |
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Rule of 78 |
2000-03-22 |
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From Dan Baumgarten:
Can you explain the rule of 78 and the reverse rule of 78? Thanks.
Answered by Claude Tardif. |
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Surface area of a sphere |
2000-03-22 |
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From Gina Wilkie:
How can I demonstrate to my middle school students the reason for the formula for the surface area of a sphere?
Answered by Walter Whiteley and Chris Fisher. |
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I am in lowest terms. |
2000-03-21 |
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From Travis Fox:
I am in lowest terms. When you double my numerator and my denominator the result is 10/15.
Answered by Penny Nom. |
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Compounding continuously |
2000-03-21 |
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From Gina:
You deposit $1500 in an account that pays 6.5% annual interest, compounded continuously. Find the balance after 10 years. I'm not sure what to do with the "compounded continuously" part.
Answered by Penny Nom. |
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Binomial coefficients |
2000-03-21 |
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From Howard Lutz:
How do you find each successive numerical term in this equation y+dy=(x+dx)5 =x5+5*x4dx+10*x3(dx)2+10*x^2(dx)3+5*x(dx)4+(dx)5 I would appreciate an explanation of the method to find the numeric coefficient in a binomial expansion
Answered by Penny Nom. |
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A system of equations in five unknowns |
2000-03-20 |
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From Will:
I have been having some problem with the following question for some time. I would appreciate any help on solving the problem or a solution. Q: Assume that a system of equations in the unknowns x1, x2, x3, x4 and x5 when converted to row echelon form gives .
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Answered by Penny Nom. |
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root(-1)* root(-1) |
2000-03-20 |
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From Michael Moran:
i squared = -1 but i squared = root(-1)* root(-1)
= root( -1*-1)
= root(1)
= 1
-1 doesn't = 1 can you help me with my question
Answered by Claude Tardif. |
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Travelling from A to B |
2000-03-20 |
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From Matt:
A car is traveling from point A to point B. Point A and point B are 30 miles apart. A car travels 30 miles an hour from point A to point B and then goes back to point A. How fast does the car have to go back to average 60 miles an hour?
Answered by Claude Tardif. |
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Six digit numbers using 1,2,5,6,7, and 9 |
2000-03-20 |
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From Rachel:
How many different six-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 six?
Answered by Claude Tardif and Denis Hanson. |
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A quantitative methods course |
2000-03-19 |
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From Mark Haberman:
Question:
Last semester, the grade distribution in a quantitative methods course had the following distribution: 10% A, 25% B, 35% C, 10% D, and 15% W (withdrew). - If this grade distribution does not change this semester, what is the probability that a randomly selected student will make at least a D?
- If this grade distribution does not change this semester, what is the probability that a randomly selected student will fail the course?
- If this grade distribution does not change this semester, what is the probability that a randomly selected student who finished that course (did not withdraw) made a grade of D or better?
Answered by Harley Weston. |
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The Terror Run |
2000-03-18 |
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From Danny Mclean:
A fairground's most popular attraction is a roller coaster ride known as the Terror Run. One stretch of track is called the Missile Path and is in the form of a parabolic curve. B is 180m horizontally from A and the highest point of the curve is 100m above A and B. A.. The owner works out a quadratic expression to describe the Missile Path. What is the expression He found? B.. A safety Engineer examined the structure and observed that points A and B were likely to be damaged due to the steepness of the Missile path near these points. The owner can see no way to make the Missile path less steep near A and B and to keep the height of the ride the same. HOW CAN IT BE DONE?
Answered by Harley Weston. |
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