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Projecting a line segment onto a plane |
2000-06-08 |
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Monica pose la question :
What is the measure of the angle determined by a 14 inch segment and its projection into a plane if the length,in inches, of the projection into the plane is 7 inches?
Penny Nom lui répond. |
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Surface area of a contact lens |
2000-06-06 |
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Evie Contreras pose la question :
I would like to know how to calculate the surface area of a contact lens with a radius of 7mm? I know that the area of a circle is pi R squared, but a contact lens has a dome.
Harley Weston lui répond. |
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8 Queens on a Chess Board |
2000-06-06 |
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Patrick McGarrity pose la question :
In the classic puzzle where you put 8 Queens on a chess board and no queen can take any other queen, I was wondering if there was multiple solutions. Obviously there's the mirror and opposite images of the way I solved it, but I was wondering how many solutions there were, and if these solutions all followed a similar pattern?
Claude Tardif lui répond. |
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Divisors of 2000 |
2000-06-06 |
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Amanda Semi pose la question :
- find the product of all the divisors of 2000
- dog trainer time has 100m of fencing to enclose a rectangular exercise yard. One side of the yard can include all or part of one side of his building. iff the side of his building is 30 m, determine the maximum area he can enclose
Claude Tardif lui répond. |
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Problems |
2000-06-06 |
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Debbie Cummins pose la question :
I am a Mum of a 12 yr.boy needing help with some math problems. I need not only the answers but how it is worked out. - Both the leftmost digit & the rightmost digit of a 4 digit number N are equal to 1. When these digits are removed, the 2 digit number thus obtained is N div by 21 Find N.
- Find all 3 digit even numbers N such that 693xN is a perfect square, that is, 693x N = k x k where k is an integer.
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Paul Betts and Claude Tardif lui répond. |
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Writing in Math |
2000-06-05 |
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Laurel pose la question :
How can I incorporate writing into my math curriculum?
Penny Nom lui répond. |
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A derivative problem |
2000-06-04 |
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Jeff Ellis pose la question :
If F(x)=(4+x)(3+2x2)2(2+3x3)3, find F'(0)
Harley Weston lui répond. |
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Percents with mixed numbers |
2000-06-04 |
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Julie pose la question :
How would you find the percent of 33 1/3 out of 90 by using fraction settup!I can do whole numbers but not mixed. This is how to do whole numbers say it was 33 of 90 33 x 90 = 2970
100 x 1 = 100
2970 divided by 100
the answer is 29.7 so how do you do it with a mixed number
Penny Nom lui répond. |
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Pi to 5 decimal places |
2000-06-03 |
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Emily pose la question :
The question is find the value for pi to 5 decimal places????
Penny Nom lui répond. |
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A centroid problem |
2000-06-02 |
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Kerstin pose la question :
An isoceles triangle has sides measuring 13 cm, 13 cm, and 10 cm. Find the distance from the centroid to the vertex of a base angle.
Harley Weston lui répond. |
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4 Color map Theorem |
2000-06-02 |
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Rick Slen pose la question :
I am challenging my students to find a map that can not be coloured using only 4 colours. I know that it is not possible, but one boy drew a map with a "country" totally surrounding all the others so of course it touched all other colours. How do I explain that this type of map is not permissable?
Denis Hanson lui répond. |
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1+4+9+16+...n^2 = n(n+1)(2n+1)/6 |
2000-06-01 |
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Shamus O'Toole pose la question :
How do you derive that for the series 1+4+9+16+25.. that S(n)=(n(n+1)(2n+1))/6
Penny Nom lui répond. |
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Sens d'un mot |
2000-06-01 |
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Edward Brisse pose la question :
Serait-il possible de connaître le sens précis du mot "PORISME". Exemple : "le porisme de Poncelet".
Claude Tradif lui répond. |
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Using the inverse sine function |
2000-05-31 |
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Nelson Rothermel pose la question :
This has me completely baffled. I have to use the laws of sine or cosine to find the angles of a triangle when I have 3 sides, so I can't go 180-x-y when I have 2 angles. Now, I have a triangle with values of 3, 7, and 9. Here are the steps I used (A,B,C are angles; a,b,c are opposite sides): angle A (16.1951 degrees): cos-1*((b2+c2-a2)/(2*b*c))
angle B (40.6011 degrees): sin-1*(b*sin(A)/a)
angle C (56.7962 degrees): sin-1*(c*sin(A)/a) If you notice, A+B+C does not equal 180. According to the book, A and B are correct, but C is supposed to be 123.2038 degrees. Why doesn't it work???
Harley Weston lui répond. |
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Powers of i |
2000-05-24 |
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Paul Fieldhouse pose la question :
What is the result of raising i to the googol power? is there a rule or pattern to raising i by increasing powers of 10?
Penny Nom lui répond. |
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