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