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