− 4 u 2 v 3 − 6 u 2 v 2 + 4 u 2 v − u 2 + 2 u v 4 − 8 u v 3 + 13 u v 2 − 8 u v + 2 u − v 4 + 4 v 3 − 6 v 2 + 4 v u v 2 {\displaystyle -{\frac {4u^{2}v^{3}-6u^{2}v^{2}+4u^{2}v-u^{2}+2uv^{4}-8uv^{3}+13uv^{2}-8uv+2u-v^{4}+4v^{3}-6v^{2}+4v}{uv^{2}}}}
