What is the Jacobian ∂(x,y)∂(u,v)\frac{\partial(x, y)}{\partial(u, v)}∂(u,v)∂(x,y) for x=u2−v2x = u^2 - v^2x=u2−v2 and y=2uvy = 2uvy=2uv?
4(u2+v2)4(u^2 + v^2)4(u2+v2)
2(u2+v2)2(u^2 + v^2)2(u2+v2)
u2+v2u^2 + v^2u2+v2
4uv4uv4uv