1. stottrupbailey

$\frac{ du }{ dt }=e ^{6u+8t}$ given that u(0)=8. So this is how I set it up $\int\limits_{}^{}e ^{-6u}du=\int\limits_{}^{}e ^{8t}dt$

2. stottrupbailey

Is that right so far?

3. nubeer

yes looks right. so far.

4. stottrupbailey

Okay, so this is what I got for my integration: $\frac{ -e ^{-6u} }{ 6 }=\frac{ e ^{8t} }{ 8 }+c$

5. stottrupbailey

and then using that u(0)=8, I found that c=-0.125.

6. stottrupbailey

I actually have already worked through this problem, but I got the wrong answer at the end so I'm trying to figure out where I'm going wrong

7. stottrupbailey

so then I end up with $\frac{ -e ^{-6u} }{ 6 }=\frac{ e ^{8t} }{ 8 }-0.125$

8. stottrupbailey

so then my final answer was u(t)=$\frac{ 1 }{ 6 }\ln(\frac{ 3 }{ 4 }e ^{8t}-\frac{ 3 }{ 4 })$

9. stottrupbailey

but the book says that isn't the right answer

10. nubeer

hmm well i also got c same as u.. well what answer book says?

11. stottrupbailey

well, it's actually webwork, so it just tells me that my answer is wrong, I'm not sure what the right answer is

12. stottrupbailey

I'm thinking something must be wrong with the way I'm doing the algebra to rearrange it in terms of u(t)?

13. nubeer

well i am not sure but the way u solved question looks fine and the answer should be the one u got..

14. stottrupbailey

hmmm. Okay. I'll ask the tutor at 8. Thanks anyway :)

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