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