Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Inverse Trigonometric Functions

Question:

If $ θ, ∈ \left[\frac{\pi}{2}, \frac{3\pi}{2}\right]$, then $ sin^{-1}(sin \theta )$ equals

Options:

$\theta $

$\pi -\theta $

$2\pi -\theta $

$-\pi -\theta $

Correct Answer:

$\pi -\theta $

Explanation:

We have,

$ θ, ∈ \left[\frac{\pi}{2}, \frac{3\pi}{2}\right]⇒ -θ, ∈\left[-\frac{3\pi}{2}, -\frac{\pi}{2}\right]⇒ \pi - θ, ∈\left[-\frac{\pi}{2}, \frac{\pi}{2}\right]$

Also, $ sin (\pi - \theta ) = sin \theta $

$∴ sin^{-1}(sin\theta )= sin^{-1} (sin(\pi - \theta )) = \pi - \theta $.