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

f is continuous at x = 4

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

Both $\underset{x\to 4-}{\lim }$ f(x) and $\underset{x\to 4+}{\lim }$ f(x) exist but are not equal