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