Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

Solve $|\sin x + \cos x| = |\sin x|+|\cos x|,\,x∈[0,2π]$.

Options:

$[0,π/2]∪[π,3π/2]∪\{2π\}$

$[0,π/2]∪[1,3π/2]∪\{5π\}$

$[2,π/2]∪[π,π/2]∪\{π\}$

$[4,π/2]∪[π,π/2]∪\{4π\}$

Correct Answer:

$[0,π/2]∪[π,3π/2]∪\{2π\}$

Explanation:

The given relation holds only when sin x and cos x have the same sign or at least one of them is zero.

Hence, $x∈[0,π/2]∪[π,3π/2]∪\{2π\}$