4 2 2 4 225*a - 30*n *a + n
225*a^4 - 30*n^2*a^2 + n^4
/ ____\ / ____\ | n*\/ 15 | | n*\/ 15 | 1*|a + --------|*|a - --------| \ 15 / \ 15 /
(1*(a + n*sqrt(15)/15))*(a - n*sqrt(15)/15)
2 / 2 2\ \- n + 15*a /
(-n^2 + 15*a^2)^2
n^4 + 225.0*a^4 - 30.0*a^2*n^2