lim x^4-1/x-1

Question

x->1-

Answer 1

lim x^4-1/x-1
x->1
= lim (x^2+1)(x^2-1)/x-1
x->1
=limit (x^2+1)(x+1)(x-1)/(x-1)
x -->1
= lim (x^2+1)(x+1)
= (2)(2) = 4