I ended up here: .
Did you forget the ?
We have: .
. . And: .
Solve for Y as a function of X:
I isolate dy on one side, then take the integral of the right. After a couple of trig substitutions, I end up here but get stuck:
I think I'm on the right track. I went with a U substitution but it just didn't look right. Any help on how to finish it is greatly appreciated!