Chapter 5.4, Problem 28E

Graph each function, considering the domain, critical points, symmetry, regions where the function is increasing or decreasing, inflection point, regions where the function is concave upward or concave downward, intercepts where possible and asymptotes where applicable. (Hint: In Exercise 21, use the result of Exercise 1 in this section. In Exercise 25-27, recall from Exercise 72 in Section 3.1 on limit that $\underset{x\to \infty }{\lim }{x}^n{e}^{-x}=0$.)

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