# Thread: hey I got some problem here if anyone can help me with my homework.. its urgent..

1. ## hey I got some problem here if anyone can help me with my homework.. its urgent..

how to simplify and make y as the subject matter?
-e^(-y)y-e^(-y)=sin^3x/3+c

it will be great if anyone can help me
thank you.

From,Nurin.

2. ## Re: hey I got some problem here if anyone can help me with my homework.. its urgent..

Hey nurininsyirah97.

You will need to introduce a transformation to find x as a function of y or y as a function of x.

Try going both ways and see what you find [Hint - x as a function of y is probably easier] and consider the inverse function problem.

3. ## Re: hey I got some problem here if anyone can help me with my homework.. its urgent..

hmm its because i am doing a calculus which is first order differential eq. using separation of variables. and Ive reached to this part. and Im stuck here for hours. can u help me? T.T

4. ## Re: hey I got some problem here if anyone can help me with my homework.. its urgent..

An obvious first step is to factor out the $e^{-y}$:
$-e^{-y}(y+ 1)= \frac{sin^3(x)}{3}+ C$.

But you will not be able to solve for y as a function of x without using the "Lambert W function". Are you required to solve for y? It looks to me like you have already solved the differential equation.

5. ## Re: hey I got some problem here if anyone can help me with my homework.. its urgent..

lambert w function? what is that?