Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Continuity and Differentiability

Question:

If $t=e^{2 x}$ and $y=\log _e t^2$, then $\frac{d^2 y}{d x^2}$ is:

Options:

0

4t

$\frac{4e^{2t}}{t}$

$\frac{e^{2t}(4t-1)}{t^2}$

Correct Answer:

0

Explanation:

The correct answer is Option (1) → 0

$t=e^{2 x}$, $y=\log _e t^2$

so $\log t=2x$

so $\frac{\log t}{2}=x,y=2\log t$

so $\frac{dx}{dt}=\frac{1}{2t}$, $\frac{dy}{dt}=\frac{2}{t}$

$\frac{dy}{dx}=4⇒\frac{d^2y}{dx^2}=0$