find dy/dx for tan(x-y)=(xy)/(x^2+y^2) So far I have sec^2(x-y)(1-dy/dx) = ((y+xdy/dx)(x^2+y^2)-(xy)(2x+2ydy/dx))/((x^2+y^2)^2) but i don't know how to get dy/dx from that thank you, blake