If z = z(u,v) = f(x(u,v); y(u,v)) is a differentiable function, where x = x(u,v) = (u^2)-(v^2); y = y(u,v) = 2uv

Show that

∂^2f/∂x^2 + ∂^2f/∂y^2 = (1/(4(u^2+v^2)))[∂^2f/∂u^2 + ∂^2f/∂v^2]

EDIT: All good, I ended up solving it on my own.

Don't know how to delete but, no need for this thread anymore.