Doing another problem:

Show that the rate of change ofAttachment 26390is proportional toy.

I know that you have to find the derivative & somehow find a constant to place in front ofy.Stuck here.

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- Dec 28th 2012, 03:01 PMzachd77proportionality of rate of change
Doing another problem:

**Show that the rate of change of**Attachment 26390**is proportional to***y.*

I know that you have to find the derivative & somehow find a constant to place in front of*y.*Stuck here. - Dec 28th 2012, 03:20 PMskeeterRe: proportionality of rate of change
- Dec 28th 2012, 03:34 PMzachd77Re: proportionality of rate of change
I got 3^(2x)*(7 ln(5))5^(7x)+5^(7x)*(2 ln(3))9^x... bit messy, best I could do to show

*y'* - Dec 28th 2012, 03:40 PMskeeterRe: proportionality of rate of change
$\displaystyle y' = 3^{2x} \cdot 7\ln{5} \cdot 5^{7x} + 5^{7x} \cdot 2\ln{3} \cdot 3^{2x}$

$\displaystyle y' = 3^{2x}5^{7x}(7\ln{5} + 2\ln{3})$

$\displaystyle y' = y(7\ln{5} + 2\ln{3})$ - Dec 28th 2012, 04:42 PMzachd77Re: proportionality of rate of change
thanks!!