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