u 4 ( − v 3 ) − u 3 v 4 + 2 u 3 v 3 − 2 u 3 v 2 − 2 u 2 v 3 + 3 u 2 v 2 − 2 u 2 v − 2 u v 2 + 2 u v − u − v u 2 v 2 {\displaystyle {\frac {u^{4}\left(-v^{3}\right)-u^{3}v^{4}+2u^{3}v^{3}-2u^{3}v^{2}-2u^{2}v^{3}+3u^{2}v^{2}-2u^{2}v-2uv^{2}+2uv-u-v}{u^{2}v^{2}}}}
