 |
|
|
|
|
|
|
|
|
Trig identity crisis |
2000-11-29 |
|
From Rhiannon:
I have tried many times to find the answer to these problems but I can't I am in grade 12 - tan(x)=csc2(x)-cot2(x)
- cos(x)/csc(x)-2sin(x)=tan(x)/1-tan(x)
- cos(x)[ tan2(x)1-1]/cos2(x)+sin2(x)=sec(x)
Answered by Harley Weston. |
|
|
|
|
|
|
Vector Problem |
2000-11-27 |
|
From Ben:
An aircraft can fly 260km/h in still air and the wind is blowing at 70km/h towards the West. In what direction should the aircraft head so that its actual velocity is on a bearing of 030 degrees?
Answered by Harley Weston. |
|
|
|
|
|
|
Power series representations |
2000-11-27 |
|
From Grace:
Is there a systematic way of finding a power series representation of a function? I understand that you have to manipulate the function so that it is of the form 1/(1-x), but beyond that I am lost.
Answered by Harley Weston. |
|
|
|
|
|
|
Order of operations |
2000-11-26 |
|
From Margaret Pratt:
My daughter has a math question and I am afraid I am of no help. Can you help? 2x5/2+1-5= She arrives at 8 as the answer and has been told this is incorrect. Any help you can give would be appreciated.
Answered by Penny Nom. |
|
|
|
|
|
|
A complex calculation |
2000-11-24 |
|
From Angie:
Multiply (3-2i)2=32-2(3)(2i)+(2i)2
Answered by Penny Nom. |
|
|
|
|
|
|
A piecewise linear equation |
2000-11-24 |
|
From Jacky:
There is a light bulb and it is given that the light bulb cost $0.75 and the cost of operating it is $0.0081 per hour. From the information give, I came up with the linear equation: Let c be total cost and Let h be hours used. Therefore: c = 0.0081h + 0.75 represents the total cost of the light bulb and the electricity. However, the second part of the question added the fact that the light bulb will only last for 800 hours. If the light bulb is replaced as soon as it burns out exactly after every 800 hours, how can I write an equation that represents that? Is it possible? What would it look like on the graph.
Answered by Harley Weston. |
|
|
|
|
|
|
racine carrée |
2000-11-24 |
|
From G. Bigorgne:
Quel est donc l'origine de l'expression "racine carrée" ? Pourquoi avoir choisi cette expression ?
Answered by Claude Tardif. |
|
|
|
|
|
|
What are adjacent angles that equal 360 called? |
2000-11-22 |
|
From David:
I know that supplementary angles add to 180 degrees and that commplementary angles add up to be 90 degrees, but what are adjacent angles that equal 360 degrees called?
Answered by Chris Fisher. |
|
|
|
|
|
|
Comparing an integral and a sum |
2000-11-21 |
|
From Douglas Norberg:
A fellow teacher asked me about a problem she wanted to give to her students. It involved whether to take a million dollars or a penny doubled a number of times. I was able to determine the number must have been .01 * 230 which is about $10 million and a lot more than $1 million. To check that I was right I used a spreadsheet and did a Riemann sum. When I finished I reasoned that I had done the task in several steps and I could have done it in 1 step. Thus I integrated .01 * 2x from 0 through 30 but the number I got was $15,490,820.0324. Why the difference?
Answered by Harley Weston. |
|
|
|
|
|
|
5 spades |
2000-11-21 |
|
From Matt:
In a standard deck of 52 card how many would you have to draw (without looking at them) to be absolutely certain that you had 5 spades?
Answered by Claude Tardif. |
|
|
|
|
|
|
Range of a function |
2000-11-21 |
|
From David Bell:
Given a rational function such as f(x) = (8x-3)/(4x-1). How can the range be found.
Answered by Penny Nom. |
|
|
|
|
|
|
Net, gross and vat |
2000-11-20 |
|
From Chris:
I have my gross but want to find out the net so I know how much the VAT is?
Answered by Penny Nom. |
|
|
|
|
|
|
Integral solutions |
2000-11-20 |
|
From David:
determine all pairs of integers (x,y) which satisfy the equation 6x2 - 3xy - 13x + 5y = -11 I got y= (6x2-13x+11)/(3x-5) and i don't konw how to continue
Answered by Claude Tardif. |
|
|
|
|
|
|
Permutations vs. combinations |
2000-11-20 |
|
From Ashleigh:
How do you tell whether the problem is a permutation or a combination?
Answered by Walter Whiteley. |
|
|
|
|
|
|
Bridges and parabolas |
2000-11-18 |
|
From Lauren:
My name is Lauren, and Im a secondary school student in Ontario. For my gr11 advanced math class I have to find out how and why parabolics are used in arch bridges and write 3 paragraphs on it. People who cohse satelites and whatnot are lucky - I've found a ton of info, but for arch bridges there seems to be nothing.
Answered by Harley Weston. |
|
|
