Compute the partial derivative fyf_yfy of the function f(x,y)=x+yx−yf(x,y) = \frac{x+y}{x-y}f(x,y)=x−yx+y for x≠yx \neq yx=y.
2x(x−y)2\frac{2x}{(x-y)^2}(x−y)22x
2y(x−y)2\frac{2y}{(x-y)^2}(x−y)22y
−2x(x−y)2-\frac{2x}{(x-y)^2}−(x−y)22x
2(x+y)(x−y)2\frac{2(x+y)}{(x-y)^2}(x−y)22(x+y)