− 2 u 2 v 4 − 4 u 2 v 3 + 5 u 2 v 2 − 4 u 2 v + u 2 − 3 u v 4 + 6 u v 3 − 7 u v 2 + 6 u v − 3 u + v 4 − 4 v 3 + 5 v 2 − 4 v + 2 u v 2 {\displaystyle -{\frac {2u^{2}v^{4}-4u^{2}v^{3}+5u^{2}v^{2}-4u^{2}v+u^{2}-3uv^{4}+6uv^{3}-7uv^{2}+6uv-3u+v^{4}-4v^{3}+5v^{2}-4v+2}{uv^{2}}}}
