Hi i have got this question but i cant do part c can anybody help with my question i attached the 2 photos ::::

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- May 7th 2012, 03:28 AMk31453Exponential Tricky Problem Solving Task
Hi i have got this question but i cant do part c can anybody help with my question i attached the 2 photos ::::

Attachment 23803Attachment 23804 - May 7th 2012, 07:10 AMemakarovRe: Exponential Tricky Problem Solving Task
I assume the equation is $\displaystyle x = At^be^{-ct}$. Using the derivative, express the maximum point (which is t = 30) through b and c. This gives you one equation. For the second equation, you can take x(4t) = x(t) / 2 where t = 30. After some cancellations, this gives you another linear equation on b and c. From these two equations you can find b and c. Then find A from x(30) = 0.2.

The answer is below (for checking only).

__Spoiler__: - May 7th 2012, 04:30 PMk31453Re: Exponential Tricky Problem Solving Task
- May 7th 2012, 04:33 PMemakarovRe: Exponential Tricky Problem Solving Task
Which exactly recommendation don't you get?

- May 7th 2012, 07:32 PMk31453Re: Exponential Tricky Problem Solving Task
The methodsbof getting answer u cant use derevitive u have to use exponential or log rules to do part c thats what teacher said

- May 8th 2012, 06:43 AMemakarovRe: Exponential Tricky Problem Solving Task
If you can't use derivatives, you can assume that the maximum of $\displaystyle At^be^{-ct}$ occurs at t = b / c. Draw several graphs for various values of b and c and verify that this is the case. The rest of the recommendations in post #2 should still work.