z 2 a 6 + 2 z 3 a 5 − z a 5 + 2 z 4 a 4 − 2 z 2 a 4 + a 4 + z 5 a 3 − z a 3 + 3 z 4 a 2 − 6 z 2 a 2 + 2 a 2 + z 5 a − 2 z 3 a + z 4 − 3 z 2 + 2 {\displaystyle z^{2}a^{6}+2z^{3}a^{5}-za^{5}+2z^{4}a^{4}-2z^{2}a^{4}+a^{4}+z^{5}a^{3}-za^{3}+3z^{4}a^{2}-6z^{2}a^{2}+2a^{2}+z^{5}a-2z^{3}a+z^{4}-3z^{2}+2}
