Question

Find the domain of the real function $\sqrt{9-x^2}$.

Answer 1

$\begin{array}{c}\sqrt{9-x^2}\\ \Rightarrow 9-x^2\ge 0\\ \Rightarrow x^2-9\le 0\\ \Rightarrow \left(x-3\right)\left(x+3\right)\le 0\\ Domainis\left[-3,3\right]\end{array}$