− 4 u v 3 − 6 u v 2 + 4 u v − u − v 3 + 4 v 2 − 6 v + 4 u v 3 / 2 {\displaystyle -{\frac {4uv^{3}-6uv^{2}+4uv-u-v^{3}+4v^{2}-6v+4}{{\sqrt {u}}v^{3/2}}}}
