− 2 u v 3 − 4 u v 2 + 4 u v − u − v 3 + 4 v 2 − 4 v + 2 u v 3 / 2 {\displaystyle -{\frac {2uv^{3}-4uv^{2}+4uv-u-v^{3}+4v^{2}-4v+2}{{\sqrt {u}}v^{3/2}}}}
