Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Calculus

Question:

If $x=6t,y=4t^3,$ then the value of $\frac{d^2y}{dx^2}$ is :

Options:

$\frac{3}{2}t $

$\frac{4}{5t}$

$\frac{4}{3t}$

$\frac{2}{3}t$

Correct Answer:

$\frac{2}{3}t$

Explanation:

The correct answer is Option (4) → $\frac{2}{3}t$

$x=6t$,         $\frac{dx}{dt}=6$

$y=4t^3$,     $\frac{dy}{dt}=12t^2$

$⇒\frac{dy}{dx}=\frac{12t^2}{6}=2t^2$

$⇒\frac{d^2y}{dx^2}=4t×\frac{dt}{dx}=4t×\frac{1}{6}$

$=\frac{2}{3}t$