Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Determinants

Question:

If $y=\frac{1}{x+1}$, then $\frac{d^2 y}{d x^2}$ at x = 2 is:

Options:

$\frac{2}{9}$

$\frac{3}{2}$

$\frac{2}{27}$

$\frac{3}{8}$

Correct Answer:

$\frac{2}{27}$

Explanation:

$y=\frac{1}{x+1}$

so differentiating y wrt x

$\frac{dy}{d x} = \frac{-1}{(x+1)^2}$

again differentiating wrt x

$\frac{d^2 y}{d x^2} = \frac{2}{(x+1)^3}$

so  $\left.\frac{d^2y}{dx^2}\right]_{x=2} = \frac{2}{(2+1)^3} = \frac{2}{3^3}$

= $\frac{2}{27}$