Solve this following

Both $\lim _{x \rightarrow 4} f(x)$ and $\lim _{x \rightarrow 4+} f(x)$ exist but are not equal

$\lim _{x \rightarrow 4-} f(x)$ exists but $\lim _{x \rightarrow 4+} f(x)$ does not exist

$\lim _{x \rightarrow 4+} f(x)$ exists but $\lim _{x \rightarrow 4-} f(x)$ does not exist

$\mathrm{f}$ is continuous at $x=4$