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Ok thanks for that it makes sense now. K should be negative in my question,

Noone else? Justy wanna know if x = a - Ae^kt satisfies dx/dt = k(a - x). Both with integration and the substitution method i found it doesn't satisfy the equation. If it does please show me how! *lol*

haha thanks. I think the question given to me is wrong. Substitution and checking is the first part of the question. In the second part, I found k is negative and subsequently found an answer for the question. Anyone else got any ideas?

shouldn't dx/dt be -kAe^kt ? (what happened to the minus sign in front of the A?

Can it be shown that x = a - Ae^kt satisfies dx/dt = k(a - x)? I trued this by substution and it doesn't work, and it's supposed to. When I did it, I found k should be negative in the first equation to make it work. Can anyone help out here? Thanks..

Smart girl! You're talking like a sociology student already. This is exactly what you will learn is a course like that. Sad but true, unfortunately..

Be careful calling the mean an average. Actually, the median and mode are also averages, though people often say 'average' they actually mean the mean. So if someone says average, ask them what average.

Is it possible for anyone to send me the statistics chapters from , say, the preliminary and HSC mathsquest books (or a similar set). I guess some of you have the disc as well as the textbook. I think there are only 2 chapters. If anyone has them, can you send to my email, culicine@hotmail.com...

Yes I checked it, and plotted for various values of 'a'. It's definately a parabola. From plotting several graphs I can calculate the maximum area of the rectangle in terms of 'a'. Though this is not very rigorous as you can't calculate for ALL values of a. Could one then prove by indiction...

Imagine you want to find the maximum area a rectangle can take when it is bounded on one of its edges by the x-axis and its opposite vertices touch a parabola (y = - x^2 + 6a^2 , where (-root6)*a < x < (root6)*a. I managed to solve this using derivatives and found the maximum area (in terms of...

I was having some trouble with the following questions. Can anyone help? Find the value of the real numbers, x and y, in the following: a. x / (1 + i) + y / (1 - 2i) = 1 b. x / (2 - i) + yi / (i - 3) = 2 / (1 + i) Thanks in advance!

Botany, indeed any of the soft sciences, can be as 'hard' as you'd like to make them. Try developing matematical/statistical models for envoronmental problems / long term changes in coral reefs / forests, whatever. Its not that easy. I think there would be a strong demand for mathematicans to go...

Thanks guys, I spotted my mistake. It was with the expansion part. I should have seen that (a+b+c)^2 is the same as ((a+b) + c)^2. Maybe I should go back to grade 8 again!

Here's an algebra problem that I hope someone can help me with. Imagine you have a right angled triangle (height = h) and base = x. The perimeter is 12 units and the area is 7 square units. Thus, 7 = 1/2.x.h (area) and 12 = h + x + sqrt (x^2 + h^2) (perimeter) These two...