Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

If $y=x^2log_ex, $ then $\frac{d^2y}{dx^2}$ is equal to :

Options:

$5+x\, log_e\, x$

$3+2\, log_e\, x$

$3+2x\, log_e\, x$

$x(1+2\, log_e, x)$

Correct Answer:

$3+2\, log_e\, x$

Explanation:

The correct answer is Option (2) → $3+2\log_e\, x$

$y=x^2\log_ex$

$\frac{dy}{dx}=2x\log_ex+x^2×\frac{1}{x}=2x\log_ex+x$

$⇒\frac{d^2y}{dx^2}=2\left(\log_ex+x^2×\frac{1}{x}\right)+1$

$=2(\log_ex+1)+1$

$=2\log_ex+3$