Pez, could you tell him that the arctan addition formula he used means the fraction should be in an arctan too? As such if you take the limit necessary to integrate, both sides go to zero without integration happening. You don't have something of the form f(x)dx, but rather f(dx) where f(0)=0.
I don't like debating someone who's decided to block me, so I'm not going to, just want to make sure he gets the answer to the question we were discussing.