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