Very simple in writing, but hard to solve: [tex] x*\frac{dy}{dx}=(y^2-y x^2)/(y^2+x^2)[/tex] :tongue2:
I tend to look at it this way: [tex](y^2-yx^2)dx-(xy^2+x^3)dy=0[/tex] but are unable to proceed. It's not exact, can't make it exact, and can't come up with any differentials by inspection.