1. The problem statement, all variables and given/known data Solve dy/dx = y/x + tan(y/x) 2. Relevant equations 3. The attempt at a solution Not separable, as far as I can tell. It's not homogeneous, since for the tan term f(λx,λy) = tan(λy/λx) = tan(y/x) ≠ λtan(y/x). It's also not of the form dy/dx + P(x)y = Q(x), because I don't think Q(x) should involve y. And that completes the list of methods I know, none of which I can use! How do you solve this?! Is there a substitution I should make?