Problem with first order separabel differential equation

Hi!

First of all I am Norwegian, and my math-english might not be totally correct.

Okay, I have a problem with a first order separabel differential equation:

http://folk.uio.no/thomaali/1.jpg where A is a real constant and 0 < y < A.

I seperate:

http://folk.uio.no/thomaali/2.jpg

Splitting the fraction and differentiate it:

http://folk.uio.no/thomaali/3.jpg

I now have to put the y on the one side of the equation, but I'm unsure of how to do this. This is as far as i have gotten:

http://folk.uio.no/thomaali/4.jpg

Is there something I am doing wrong in the steps above?

Any help would be greatly appreciated!

Thank you in advance,

Thomas