− z 2 a 12 − a 12 + z 4 a 10 + 2 z 2 a 10 + a 10 − 2 z 2 a 8 − 2 a 8 + z 6 a 6 + 6 z 4 a 6 + 9 z 2 a 6 + 3 a 6 {\displaystyle -z^{2}a^{12}-a^{12}+z^{4}a^{10}+2z^{2}a^{10}+a^{10}-2z^{2}a^{8}-2a^{8}+z^{6}a^{6}+6z^{4}a^{6}+9z^{2}a^{6}+3a^{6}}
