Answer
3
Work Step by Step
see: Rules for Limits
Let $a, A$, and $B$ be real numbers,
and let $f$ and $g$ be functions such that
$\displaystyle \lim_{x\rightarrow a}f(x)=A$ and $\displaystyle \lim_{x\rightarrow a}g(x)=B$.
6. For any real number $k,\displaystyle \lim_{x\rightarrow a}[f(x)]^{k}=[\lim_{x\rightarrow a}f(x)]^{k}=A^{k}$,
provided this limit exists.
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$\displaystyle \lim_{x\rightarrow 4}\sqrt{f(x)}=\lim_{x\rightarrow 4}[f(x)^{1/2}]$
$=[\displaystyle \lim_{x\rightarrow 4}f(x)]^{1/2}$
$=9^{1/2}=3$
