1. The problem statement, all variables and given/known data Evaluate the integral: integral of dx / (4+x^2)^2 2. Relevant equations x = a tan x theta a^2 + x^2 = a^2 sec^2 theta 3. The attempt at a solution x = 2 tan theta dx = 2sec^2 theta tan theta = x/2 integral of dx / (4+x^2)^2 = 1/8 integral (sec^2 theta / sec^4 theta) d theta = 1/8 integral (cos^2 theta) dtheta = 1/16 integral 1 + cos 2 theta d theta = 1/16 [ theta + sin 2 theta / 2 ] + c = 1/16 [ theta + sin theta cos theta ] + c = 1/16 [ tan ^-1 x/2 + ??? ] + c "???" is where I get lost. Did I do the problem wrong? I was really confused when the book gave me a problem without a square root.