Question

The domain of the real function $f\left(x\right)=\frac{1}{\sqrt{25-4x^2}}$ is

• A. (-5, 5)
• B. (-2, 2)
• C.
• D.

Answer 1

The correct option is C

$25-4x^2>0\Rightarrow 4x^2-25=0$
$\Rightarrow (2x+5)(2x-5)<0$
$\Rightarrow xϵ(\frac{-5}{2},\frac{5}{2})$