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Three chords |
2001-06-28 |
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From Paul:
AE is a diameter of a circle and AC, CD and DE are chords of lengths 1, 2 and 3 respectively. (See the diagram.) Find the ridius of the circle.
Answered by Harley Weston. |
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Three tangents to a circle |
2001-06-27 |
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From Stephanie:
The three lines PS, PT, and RQ are tangents to the circle. The points S, X, and T are the three points of tangency. Prove that the perimeter of triangle PQR is equal to 2PT.
Answered by Chris Fisher. |
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A three legged stool |
2001-06-27 |
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From Teri:
I wanted to know why a three legged stool is always steady, and why a four legged stool is not. I am wanting to know the mathematical reasoning behind this.
Answered by Walter Whiteley. |
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A phone bill |
2001-06-18 |
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From Janet:
What is the formuala to calculate cost per minute? Here is the data below # of calls - 238
# of minutes - 443
cost - $70.06
Answered by Penny Nom. |
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Two log problems |
2001-06-16 |
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From A student:
Hi..this is one of 9th grade student in Fort Worth TX. well..I am doing EPGY stuffs in my school right now..and.. me and my teacher had problems to solve some advanced logarithmic thing. so I searched some sites to solve these two questions - (log base 7 * 10) * (log base 10 * X ) = 2
- log base 10 * (3x-4) + log base 12 * X
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(log base 12 * 2) + (log base 12 * 5)
= log base 10 *4
Answered by Harley Weston. |
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A calculation with 6 numbers |
2001-06-16 |
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From Edwin:
I'm asked to come with, and program (in Ansi -C) an algorithm that calculates all the possible results of a calculation with 6 numbers and one result. For example: I want all calculations with the numbers 3, 3, 8, 8, 2, 9, and with a result of 786. all numbers may be used once, arithmetical operations allowed are + - / *, fractions are not allowed. The problem here is what is a fast method to do this (i.e. what's algorithm that can to this).
Answered by Claude Tardif. |
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A factoring problem |
2001-06-14 |
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From A student:
What is the factoring of x squared -7+6 equal
Answered by Penny Nom. |
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Primes and square roots |
2001-06-14 |
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From Paul:
I have a bit of a math problem. It has to do with determining if a very large number is a prime. One method entails dividing the number by every smaller prime number. If any divide into it, it's not a prime. This would be a big job if the number was something like 400 digits long. Another way I read about was to take the square root of the number and test all the primes less than its square root. The explanation went like this: "When a number is divided by another number that is greater than its square root, the result is a number smaller than the square root. For example, the square root of 36 is 6. Dividing 36 by 2, a smaller number than 6, gives 18, a number that is larger than the square root. To prove that 37 is prime it is only necessary to divide it by primes less than 6, since if it had a prime factor greater than 6, it would have to have one less than 6 as well." I understand the explanation, up to the last sentence. I fail to see the underlying logic. Why if a prime factor exists below the square does one have to exist above the square too? The number 40 can be divided by the prime 2, a number below its square root, but no other primes can do this above its square root. Have I missed something? What's the logic here?
Answered by Claude Tardif and Penny Nom. |
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Euclid and Pythagoras |
2001-06-14 |
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From Scott:
Question 1. In about 300 BC Euclid recorded a proof of Pythagoras rule. Disscuss Euclid's contribution to developing the theroem. Question 2. Why was it named after Pyhagoras if he did not orginally discover it?
Answered by Chris Fisher. |
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Area between curves |
2001-06-13 |
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From Phil:
question 1 find the area bound by the curves y = x2 + 2x + 3 and y = 2x + 4 question 2 Find the volume generated by rotating the curve x2 + y2 = 9 about the x-axis
Answered by Harley Weston. |
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Un nombre entier relatif ou reel |
2001-06-13 |
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From Omar:
J'aimerais savoir c'est quoi un nombre entier relatif ou réel?
Answered by Claude Tardif. |
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An inequality involving triangles |
2001-06-12 |
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From Sandra:
The triangle inequality guarantees that the sum of the lengths of two sides of a triangle is greater than the length of the third. As a consequence, if x and y are legs of a right triangle, with x less than or equal to y, and z the hypotenuse, then x + y is greater than z, so x is greater than z - y. Under what circumstances will x is greater than 2(z - y) be true?
Answered by Chris Fisher and Penny Nom. |
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Monthly payments |
2001-06-12 |
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From Anthony:
This question is base on my interest. I would like to know the formula for calculating this example: If you borrow $10,000 from a bank with an APR of 11.7% to be paid off in 5 years, what is your monthly payment?
Answered by Penny Nom. |
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5+5+5=550 |
2001-06-11 |
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From Tom:
I am in algebra and my teacher gave us an equation that was not true. she told us that we could only use one line segment(it can't bend turn has to be straight) to make the equation true. here is the equation: 5+5+5=550. i have not figured it out but have tried many things and believe it is not mathmatical but cross a # or sign out.also i forgot you can't put a slash mark through the equals sign.
Answered by Penny Nom. |
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Geometry problems involving triangles |
2001-06-07 |
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From Sandi:
Find the radius of the largest circle contained in a right triangle whose legs are 8 and 15 and hypotenuse is 17. If the right triangle has legs a and b and hypotenuse c, find an expression for the radius of the circle.
Answered by Penny Nom. |
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