4 x - 1
x^4 - 1
(x + 1)*(x - 1)*(x + I)*(x - I)
(((x + 1)*(x - 1))*(x + i))*(x - i)
-1.0 + x^4
/ 2\ (1 + x)*\1 + x /*(-1 + x)
(1 + x)*(1 + x^2)*(-1 + x)