1. The problem statement, all variables and given/known data Evaluate the integral: ∫(0 to ∞) [dv/((1+v^2)(1+tan^-1(v))] 2. Relevant equations U-substitution, taking limit to evaluate improper integrals 3. The attempt at a solution http://imgur.com/CjkRF As you can see in the image, I try u-substitution and then take the integral. I end up with ln(0), though, because arctan(0) = 0. The correct answer is ln(1 + ∏/2), but I'm not sure how to get there.