Chapter 4.3, Problem 46ES

Using $\text{L'H <mover accent="true"> o <mo> ^ </mo> </mover>pital's}$ rule (Section 3.6) one can verify that $\underset{x\to +\infty }{\lim }\frac{e^x}{x}=+\infty ,\underset{x\to +\infty }{\lim }\frac{x}{e^x}=0,\underset{x\to -\infty }{\lim }x{e}^x=0$

In these exercises: (a) Use these results, as necessary, to find the limits of $f\left(x\right)$ as $x\to +\infty$ and as $x\to -\infty$ . (b) Sketch a graph of $f\left(x\right)$ and identify all relative extrema, inflection points, and asymptotes (as appropriate). Check your work with a graphing utility.

$f\left(x\right)=x{e}^{-x}$