− z 6 a 4 + z 4 a 2 − 5 z 4 a 4 + z 4 a 6 + 4 z 2 a 2 − 8 z 2 a 4 + 3 z 2 a 6 + 4 a 2 − 5 a 4 + 2 a 6 {\displaystyle -{\frac {z^{6}}{a^{4}}}+{\frac {z^{4}}{a^{2}}}-{\frac {5z^{4}}{a^{4}}}+{\frac {z^{4}}{a^{6}}}+{\frac {4z^{2}}{a^{2}}}-{\frac {8z^{2}}{a^{4}}}+{\frac {3z^{2}}{a^{6}}}+{\frac {4}{a^{2}}}-{\frac {5}{a^{4}}}+{\frac {2}{a^{6}}}}
