− 2 u 2 v 3 − 4 u 2 v 2 + 4 u 2 v − u 2 + 2 u v 4 − 6 u v 3 + 9 u v 2 − 6 u v + 2 u − v 4 + 4 v 3 − 4 v 2 + 2 v u v 2 {\displaystyle -{\frac {2u^{2}v^{3}-4u^{2}v^{2}+4u^{2}v-u^{2}+2uv^{4}-6uv^{3}+9uv^{2}-6uv+2u-v^{4}+4v^{3}-4v^{2}+2v}{uv^{2}}}}
