Chapter 1.2, Problem 4QCE

Let $f\left(x\right)=\left\{\begin{array}{cc}x+1,& x\le 1\\ x-1,& x>1\end{array}\right.$

Find the limits that exist.

(a) $\underset{x\to 1^{-}}{\lim }f\left(x\right)=\text{\_\_\_\_\_\_\_}$

(b) $\underset{x\to 1^{+}}{\lim }f\left(x\right)=\text{\_\_\_\_\_\_\_}$

(c) $\underset{x\to 1}{\lim }f\left(x\right)=\text{\_\_\_\_\_\_\_}$