4 2 - y + y - 1
-y^4 + y^2 - 1
/ ___\ / ___\ / ___ \ / ___\ | I \/ 3 | | I \/ 3 | | \/ 3 I| | I \/ 3 | |x + - + -----|*|x + - - + -----|*|x + - ----- + -|*|x + - - - -----| \ 2 2 / \ 2 2 / \ 2 2/ \ 2 2 /
(((x + i/2 + sqrt(3)/2)*(x - i/2 + sqrt(3)/2))*(x - sqrt(3)/2 + i/2))*(x - i/2 - sqrt(3)/2)
2 4 -1 + y - y
-1 + y^2 - y^4
2 / 2\ -1 + y *\1 - y /
-1 + y^2*(1 - y^2)
-1.0 + y^2 - y^4