Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Continuity and Differentiability

Question:

If $x=4 t^2, y=8 t$, then $\frac{d^2 y}{d x^2}$ is:

Options:

$\frac{1}{t}$

$-\frac{1}{8 t}$

$-\frac{1}{8 t^3}$

$-\frac{1}{t^2}$

Correct Answer:

$-\frac{1}{8 t^3}$

Explanation:

The correct answer is Option (3) → $-\frac{1}{8 t^3}$

$x=4 t^2, y=8 t$

$\frac{dx}{dt}=8t$

$\frac{dy}{dt}=8$

$⇒\frac{dy}{dx}=\frac{1}{t}⇒\frac{d^2y}{dx^2}=-\frac{1}{t}\frac{dt}{dx}=-\frac{1}{8 t^3}$

$\frac{d^2y}{dx^2}=-\frac{1}{8 t^3}$