(1−a4)−b2(4−b2)\left(1-a^{4}\right)-b^{2}\left(4-b^{2}\right)(1−a4)−b2(4−b2)
2a(1+a2+b2)2 a\left(1+a^{2}+b^{2}\right)2a(1+a2+b2)
(1+a2+b2)3\left(1+a^{2}+b^{2}\right)^{3}(1+a2+b2)3
−2a(1+a2+b2)-2 a\left(1+a^{2}+b^{2}\right)−2a(1+a2+b2)
