Chapter 5.4, Problem 16P

Find the Jacobians $\partial \left(x,y\right)/\partial \left(u,v\right)$ of the given transformations from variables $x,y$ to variables $u,v$     $x=\frac{1}{2}\left(u^2-v^2\right),$     $y=uv,$ ( $u$ and $v$ are called parabolic cylinder coordinates).