Question

Find the domain of definition of the function $f\left(x\right)=\sqrt{9-x^2}$.

Answer 1

The given function $f\left(x\right)=\sqrt{9-x^2}$ will be defined if

$9-x^2\ge 0$

or, $x^2\le 9$

or, $-3\le x\le 3$.

So the domain of the definition of the function will be $[-3,3]$.