The curve is given by x^2+2r(sqrt(y))=xy

What is dx/dy when r is constant?

2x + r(y)^(-1/2) dy/dx = x dy/dx + y

dy/dx (r(y)^(-1/2) - x) = y - 2x
dy/dx = (y - 2x)/(r(y)^(-1/2) )