## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

The limit is $0$.
We see that as we move from the left and the right toward the $x$ value of $4$, the $y$ value tends toward $0$. Since the left and right limits agree, the overall limit exists and is equal to $0$. This is true even though $f(4)$ does not exist (hole at $x=4$).