− ( u − 1 ) ( v − 1 ) ( u 2 v 2 − 2 u 2 v + u 2 − 2 u v 2 + 6 u v − 2 u + v 2 − 2 v + 1 ) u 3 / 2 v 3 / 2 {\displaystyle -{\frac {(u-1)(v-1)\left(u^{2}v^{2}-2u^{2}v+u^{2}-2uv^{2}+6uv-2u+v^{2}-2v+1\right)}{u^{3/2}v^{3/2}}}}
