− 2 u 2 v − u 2 + 2 u v 4 − 2 u v 3 + u v 2 − 2 u v + 2 u − v 4 + 2 v 3 u v 2 {\displaystyle -{\frac {2u^{2}v-u^{2}+2uv^{4}-2uv^{3}+uv^{2}-2uv+2u-v^{4}+2v^{3}}{uv^{2}}}}
