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