If $y=6x+\frac{4}{x}$ then $\frac{d^2y}{dx^2}$ at $x=2$ is :
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 1
$y=6x+\frac{4}{x}$
$⇒\frac{dy}{dx}=6-\frac{4}{x^2}$
$⇒\frac{d^2y}{dx^2}=\frac{4×2}{x^2}=\frac{8}{x^2}$
$\left.\frac{d^2y}{dx^2}\right|_{x=2}=\frac{8}{8}=1$