Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Inverse Trigonometric Functions

Question:

If $tan^{-1} x + 2 cot^{-1}x =\frac{2\pi}{3}$, then x =

Options:

3

$\sqrt{3}$

$\sqrt{2}$

$\frac{\sqrt{3}-1}{\sqrt{3}+1}$

Correct Answer:

$\sqrt{3}$

Explanation:

$tan^{-1} x + 2 cot^{-1}x =\frac{2\pi}{3}$

$⇒ tan^{-1}x + 2\left(\frac{\pi}{2}-tan^{-1}x\right)=\frac{2\pi}{3}⇒ tan^{-1}x =\frac{\pi}{3}⇒x = \sqrt{3}$