u 2 v 4 − 4 u 2 v 3 + 6 u 2 v 2 − 4 u 2 v − 3 u v 4 + 9 u v 3 − 13 u v 2 + 9 u v − 3 u − 4 v 3 + 6 v 2 − 4 v + 1 u v 2 {\displaystyle {\frac {u^{2}v^{4}-4u^{2}v^{3}+6u^{2}v^{2}-4u^{2}v-3uv^{4}+9uv^{3}-13uv^{2}+9uv-3u-4v^{3}+6v^{2}-4v+1}{uv^{2}}}}
