1. The problem statement, all variables and given/known data 1+x^2 dy/dx = 1+y^2 2. Relevant equations 3. The attempt at a solution if I clean this up a little, I would get 1/ (1+x^2) dx = 1/ (1+y^2) dy correct? since the integral of 1+x^2 is arctanX, I get arctanX + C = arctanY + C. And I don't know what to do from here. Please help!