Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Inverse Trigonometric Functions

Question:

If $x+\frac{1}{x}=2,$ then principal value of $sin^{-1}x$ is :

Options:

$\pi $

$\frac{\pi }{4}$

$\frac{\pi }{2}$

$\frac{3\pi }{2}$

Correct Answer:

$\frac{\pi }{2}$

Explanation:

The correct answer is Option (3) → $\frac{\pi }{2}$

$x+\frac{1}{x}=2$

so $\frac{x^2+1}{x}=2$

so $x^2+1=2x$

$x^2-2x+1=0⇒(x-1)^2=0⇒x=1$

$\sin^{-1}(1)=\frac{\pi }{2}$