## Calculus: Early Transcendentals 8th Edition

$\lim\limits_{x \to -\infty}x^3 = \infty$
Let $f(x) =x^3$ This function is defined on the interval $(-\infty,\infty)$ Let $M \gt 1$ be given. Let $N = M$ Suppose that $x \gt N$ Then: $x^3 \gt x \gt N = M$ Therefore, $\lim\limits_{x \to \infty}x^3 = \infty$