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Five |
2001-04-21 |
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From Billie:
If One is single, two is twin, three is triple, four is quadruple, five is ????? what is five and where would I find the rest of the numbers,six, seven, eight, nine, etc.
Answered by Penny Nom. |
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Repeating decimals |
2001-04-21 |
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From Sarah:
Hi, I'm working on a project for school. The theory I choose was "When turned into a fraction, a repeating decimal has a denometor that is a multiple of three." I have a couple of questions about this topic. My first question is, have you ever heard of this, and what can you tell me about it? My second question is, when I was testing this theory I came across .999... now, when this is a fraction it is 9/9 which is equal to one. The denometor is a multiple of 3, but it's a whole number. I don't understand how a decimal can be equal to a whole number since a decimal is a piece of a whole number. Please don't just show me a math problem, I don't want to see a math problem. I want to see an explanation of this theory and the decimal .999...
Answered by Penny Nom. |
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Geometry |
2001-04-21 |
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From Rebecca:
How do you prove the following:
Let CD be an altitude of triangle ABC and assume that angle C=90 degrees. Let r1 and r2 be the inradii of triangle CAD and CBD, respectively, and show that r+r1+r2=CD, where r is the inradius of triangle ABC.
Answered by Chris Fisher. |
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Two boats |
2001-04-19 |
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From Pat:
Two boats head directly toward each other, one of them traveling 12 miles per hour and the other traveling 17 miles per hour. They begin at a distance of 20 miles from each other. How far apart are they one minute before they collide?
Answered by Penny Nom. |
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Pyramids |
2001-04-18 |
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From Kelly:
I'm in tenth grade and I know that there's some formula for finding out the slope of the side of a pyramid. I thought it could be the pythagorean therom, but I'm not sure if this works. Please send me the formula as soon as possible, I need it for a project.
Answered by Penny Nom. |
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A geometry proof |
2001-04-18 |
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From Melissa:
Extend the bisectors of angle A, angle B, and angle C of triangle ABC to meet the circumcircle at points X, Y, and Z respectively. Show that I is the orthocenter of triangle XYZ.
Answered by Chris Fisher. |
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The number of occurrences of 0 is __, of 1 is __, of... |
2001-04-17 |
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From Martyanne:
"In this sentence the number of occurrences of 0 is __, of 1 is __, of 2 is __, of 3 is __, of 4 is __, of 5 is __, of 6 is __, if 7 is __, of 8 is __, of 9 is __."
Each blank is to be filled with a numeral of one or more digits, written in decimal notation.
Answered by Claude Tardif. |
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Isoscles and scalene |
2001-04-17 |
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From Autumn:
explain where the term isoscles and scalene came from?
Answered by Chris Fisher. |
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coercif |
2001-04-17 |
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From Sonia:
J'ai juste une petite question de vocabulaire à vous soumettre: connaitriez vous la traduction en anglais du mot : "coercif", que je n'arrive pas à trouver sur le net!
Answered by Claude Tardif. |
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Differentiation |
2001-04-17 |
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From Esther:
Could you please tell me what the first derivative is of the following: y = 2/(2x+e2x) Is it (1+xe2x)/(2x+e2x)2 or perhaps -4(1+e2x)/(2x+e2x)2 ? I am a little confused between the two!
Answered by Harley Weston. |
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Solving some equations |
2001-04-16 |
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From Justin:
Solve the following equations for x
- x+7=10
x=
- x-7=10
x=
- 3x=7
x=
- x/3=10
x=
- .
- .
- .
- .
Answered by Penny Nom. |
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Leukemia |
2001-04-15 |
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From Don:
Assume: Leukemia occurs at an incidence of 1 in 10,000. Benzene is a known carcinogen which causes Leukemia and has been found in toxic levels in the homes of a community of 1200 people. Question: How many cases of Leukemia would be necessary to reject the null hypothesis. That is, to suggest that statistically, the cases are more likely due to benzene exposure rather than chance.
Answered by Chris Fisher and Penny Nom. |
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Constructing an equilateral triangle |
2001-04-14 |
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From Peggy:
Please send directions to make an equilateral triangle in plane geometry. I want each student to draw two, cut them out, and place them together to form a Jewish Star.
Answered by Penny Nom. |
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The sides of an octagon |
2001-04-13 |
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From Craig:
How do I figure the length of the sides of an octagon when all I know is the diameter (4.375).
Answered by Penny Nom. |
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1 = 0.999... |
2001-04-13 |
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From Joan:
I have a middle grade math question for you. I would like to know why .9999... = 1 ? I can not use algebra to show this or the following: We agree that 2 = 2 and that 2-2 = 0, so
1.00000......
-0.99999.....
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0.000000......
and
0.000... = 0 therefore 0.9 = 1 ----------OR--------------- 1/3 = 0.333333 and 3 X 1/3 = 1, so if 3 X 0.333... = 0.999... then 0.999... = 1 My teacher says that I can not use the above example to show why this is true, and that I must use a couple different examples. He says that there are several other ways. Do you know any? I could really use the help because I can't think of any other ways to show this is true. Thanks for any help you can give.
Answered by Penny Nom. |
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