Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Continuity and Differentiability

Question:

If $y=\tan ^{-1} x$ then $\frac{dy}{dx}$ at $y=\frac{\pi}{3}$ is equal to:

Options:

1

$\frac{1}{2}$

$\frac{1}{3}$

$\frac{1}{4}$

Correct Answer:

$\frac{1}{4}$

Explanation:

The correct answer is Option (4) → $\frac{1}{4}$

$\frac{dy}{dx}=\frac{1}{1+x^2}⇒\left.\frac{dy}{dx}\right]_{at\,y=\frac{\pi}{3}}$

$\tan^{-1}x=\frac{\pi}{3}⇒x=\sqrt{3}$

$\frac{dy}{dx}=\frac{1}{1+{\sqrt{3}}^2}$

$=\frac{1}{4}$