1. The problem statement, all variables and given/known data This is the very last piece of an integration using partial fractions question. I have to integrate 1/x2+1. 2. Relevant equations Tan2x + 1 = Sec2x 3. The attempt at a solution Substitute tanu=x: 1/tan2u + 1 = 1/sec2u = cos2u which leaves me with int [ cos2u ] .dx I'm not sure what to do from here. Or if what I've done is correct.