let $f:\mathbb{R} \rightarrow\mathbb{R}$ be a continuous function in $x_0\in\mathbb{R}$.
In addition, $f'(x)$ is defined for every $x\in(x_0-\delta,x_0+\delta),x_0\notin(x_0-\delta,x_0+\delta)$
In addition, i know that $\underset{x_0}{lim} f'(x)=L$
how can i prove that $f(x)$ Differentiable in $x_0$ ?
at first, i thought that we can use the Mean value theorem,but i'm not sure if the conditions are sufficient.