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