Question

d/dx((x^2+y^2)^2)=d/dx(x^2-y^2),求（化简）dy/dx=?

Answer 1

求导得：

2(x^2+y^2)(2x+2yy')=2x-2yy'

x-2x(x^2+y^2)=(2y(x^2+y^2)+y)y'

y'=[x-2x(x^2+y^2)]/(2y(x^2+y^2)+y)