u 2 v 3 − 3 u 2 v 2 + 3 u 2 v − u 2 + u v 4 − 5 u v 3 + 7 u v 2 − 5 u v + u − v 4 + 3 v 3 − 3 v 2 + v u v 2 {\displaystyle {\frac {u^{2}v^{3}-3u^{2}v^{2}+3u^{2}v-u^{2}+uv^{4}-5uv^{3}+7uv^{2}-5uv+u-v^{4}+3v^{3}-3v^{2}+v}{uv^{2}}}}