Limit x tends to infinity ((x+1)(x+2)(x+3))^1/3-x=?

1 Answer
Apr 19, 2018

1

Explanation:

(x+1)(x+2)(x+3) = x^3+bx^2+cx+d

root(3)((x+1)(x+2)(x+3)) = root(3)(x^3+bx^2+cx+d)

= root(3)(x^3(1+b/x+c/x^2+d/x^3)) " " for x != 0

= xroot(3)(1+b/x+c/x^2+d/x^3)) " " for x != 0

So

lim_(xrarroo)((x+1)(x+2)(x+3))^(1/3)/x = lim_(xrarroo)root(3)(1+b/x+c/x^2+d/x^3)

= root(3)(1+0+0+0) = 1