Let $f$ be a function from $(0,\infty) \to \mathbb{R}$ that is differentiable and satisfies the following:

\begin{align}
\lim\_{x \to 0^+} f(x) &= \infty\\
\lim\_{x \to \infty} f(x) &= -2.
\end{align}

Prove that there is a point $x\_0$ of the domain so that $f'(x\_0)=-1$.