Verify Clairaut's theorem for u=ln(x^(2)-y^(2)).

Answer 1

∂u/∂x = 2x/(x^2-y^2)
∂u/∂y = -2y/(x^2-y^2)

∂²u/∂x∂y = ∂²u/∂y∂x = -2(x^2+y^2)/(x^2-y^2)^2