Chapter 2: Limits and Continuity - Section 2.2 - Limit of a Function and Limit Laws - Exercises 2.2 - Page 56: 9

$f(x)$ does not need to be defined at $x=1$

The existence and non-existence of the $\lim\limits_{x \to c}f(x)=l$ does not depend on whether the function is defined or not defined at x=c. Thus, the function $f(x)$ cannot be defined at $x=1$so, the limit of the function cannot be determined.