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