Question

The domain of $f\left(x\right)=\sqrt{25-x^2}$ is

• A. $(-\infty ,-5)$
• B. $(5,\infty )$
• C. $[-5,5]$
• D. $[-\infty ,\infty ]$

Answer 1

The correct option is C $[-5,5]$

$25-x^2\ge 0$
$\Rightarrow (x-5)(x+5)\le 0$
$\Rightarrow x\in [-5,5]$
$(x-5)$ & $(x+5)$ should have opp sign