I just want to make sure I got this integration by parts thing right...
(where X(y) is the integral of x(y))
Does that look all right? And then the derivative of this result w.r.t. y would be...
[Edit: Nevermind! I just realized that the first term in the integral can be treated as a constant, so no need for integration by parts.]
[Edit again: Nevermind the last edit. That was a bad idea. Nonetheless I have figured out the problem.]