1. The problem statement, all variables and given/known data Solve the differential equation dy/dx = 3x2(1+y2)3/2 2. Relevant equations 3. The attempt at a solution So far this is what I have (I'm almost finished) - ∫dy/(1+y)3/2 = ∫3x2 dx Let y = tan(u) , dy = sec2(u) Then (1+y2)3/2 = (tan2(u)+1)3/2 = sec3(u) and u = tan-1(y) ∫cos(u)du = ∫3x2dx sin(u)+c = x3+c sin(tan-1(y)) = x3+C One question here, how do I simplify the left-hand side? I seem to have forgotten. Thanks!