Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

The slope of the normal to the curve $y=x^3-4 \sin x$ at x = 0 is:

Options:

-4

$\frac{1}{4}$

4

$-\frac{1}{4}$

Correct Answer:

$\frac{1}{4}$

Explanation:

The correct answer is Option (2) → $\frac{1}{4}$

$y=x^3-4 \sin x$

$⇒\frac{dy}{dx}=3x^2-4\cos x$

and,

$\left.\frac{dy}{dx}\right|_{x=0}=3(0)^2-4\cos (0)$

$=-4$

∴ Slope of the normal, $m=\frac{1}{4}$  $[m×\frac{dy}{dx}=-1]$