− 2 v u 4 + 2 u 4 − 2 v 2 u 3 + 7 v u 3 − 3 u 3 + 3 v 2 u 2 − 9 v u 2 + 3 u 2 − 3 v 2 u + 7 v u − 2 u + 2 v 2 − 2 v {\displaystyle -2vu^{4}+2u^{4}-2v^{2}u^{3}+7vu^{3}-3u^{3}+3v^{2}u^{2}-9vu^{2}+3u^{2}-3v^{2}u+7vu-2u+2v^{2}-2v}
