I am suppose to evaluate the integral of 1/(x^2 + 1) from 1 to infinity.

So I evaluated it from 1 to b and then took the antiderivative and got the inverse tan of b - inverse tan of 1. I think this integral converges at -pi/2 but the answer shows it converges at pi/4. Can somone tell me what I am doing wrong? I know that as be gets very large the inverse tan of it goes to zero but I can not figure out how to get pi/4!!!!! Thanks to all of you out there who help!