Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Calculus

Question:

If $x=log_et, y=\frac{1}{t}$ then $\frac{d^2y}{dx^2}+\frac{dy}{dx}$ is equal to:

Options:

0

$2e^{-x}$

$e^x$

$-2e^{-x}$

Correct Answer:

0

Explanation:

The correct answer is Option (1) → 0

$y=\frac{1}{t}$ and $x=\log t$

$⇒\frac{dy}{dt}=-\frac{1}{t^2}$ and $\frac{dx}{dt}=\frac{1}{t}$

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

$∴\frac{d^2y}{dx^2}+\frac{dy}{dx}=0$