/ ____________\ / ____________\ / ____________\ / ____________\ | / ____ | | / ____ | | / ____ | | / ____ | \a + I*\/ 4 - \/ 15 /*\a - I*\/ 4 - \/ 15 /*\a + I*\/ 4 + \/ 15 /*\a - I*\/ 4 + \/ 15 /
(((a + i*sqrt(4 - sqrt(15)))*(a - i*sqrt(4 - sqrt(15))))*(a + i*sqrt(4 + sqrt(15))))*(a - i*sqrt(4 + sqrt(15)))
2 / 2\ -1 + a *\-8 - a /
-1 + a^2*(-8 - a^2)