/ 4\ | -1 + x | lim |-1 + -------| x->1+| 2 | \ x /
Limit(-1 + (-1 + x^4)/x^2, x, 1)
-1
= -1
/ 4\ | -1 + x | lim |-1 + -------| x->1-| 2 | \ x /
-1.0