2 u 2 v 3 − 7 u 2 v 2 + 6 u 2 v − 2 u 2 + u v 4 − 8 u v 3 + 13 u v 2 − 8 u v + u − 2 v 4 + 6 v 3 − 7 v 2 + 2 v u v 2 {\displaystyle {\frac {2u^{2}v^{3}-7u^{2}v^{2}+6u^{2}v-2u^{2}+uv^{4}-8uv^{3}+13uv^{2}-8uv+u-2v^{4}+6v^{3}-7v^{2}+2v}{uv^{2}}}}