Let f be a differentiable function such that f(1)=2 and f^′(x)=f(x) for all x ∈ R. If h(x)=f(f(x)), then h^′(1) is equal to:

Let $\displaystyle f$ be a differentiable function such that $\displaystyle f(1)=2$ and $\displaystyle f^{\prime}(x)=f(x)$ for all $\displaystyle x \in \mathbf{R}$. If $\displaystyle h(x)=f(f(x))$, then $\displaystyle h^{\prime}(1)$ is equal to: