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# Differential equations C4 watch

1. hello, i need help with this question. i have answered part a with but am not sure if this part is correct. i am also having trouble setting up a differential equation for the second part of the question, could anybody give me any tip? thanks

2. But, rather:

So:

Then use the information in part ii to determine k.
3. (Original post by Qwertish)

But, rather:

So:

Then use the information in part ii to determine k.
right, thankyou. would then or ?

4. I think that should be right. Remember that dA and dt are changes, not fixed values.

EDIT: This is wrong. Ignore it.
5. (Original post by Qwertish)

I think that should be right. Remember that dA and dt are changes, not fixed values.
okay, i have identified k as being

could you help me with regards as to what i then do with this value of k and how i setup my equation?
6. Wait. No. ****. Sorry, ignore my last post.

You need to integrate both sides to get an equation like t=f(A) where f(A) is some function of A. Have you done splitting the variables yet? Then you put in A and t values from part ii to get k.

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