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