− v 2 u 3 + v u 3 − 2 v 3 u 2 + 4 v 2 u 2 − 4 v u 2 + 2 u 2 + 2 v 3 u − 4 v 2 u + 4 v u − 2 u + v 2 − v {\displaystyle -v^{2}u^{3}+vu^{3}-2v^{3}u^{2}+4v^{2}u^{2}-4vu^{2}+2u^{2}+2v^{3}u-4v^{2}u+4vu-2u+v^{2}-v}
