Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

The domain of definition of the function $f(x)=-\frac{1}{\sqrt{|x|-x}}$ is

Options:

$R$

(0, ∞)

(–∞, 0)

none of these

Correct Answer:

(–∞, 0)

Explanation:

If $x ≥ 0, | x | – x > 0 ⇒ x – x > 0$, No solution

If $x < 0, | x | – x > 0 ⇒ –x – x > 0, 2x < 0 ⇒ x ∈ (–∞, 0)$