Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Applications of Derivatives

Question:

Maximum value of logx/x in interval [2 , ∞] is

Options:

log2/2

0

1/e

1

Correct Answer:

1

Explanation:

$f'(x)=\frac{1}{x^2}(1-\ln x)$

Clearly f(x) increasing for x < e and decreases for x > e

⇒ x = e is the point of local maxima

∴  maximum f(x) = $\frac{1}{e}$

Hence (4) is the correct answer.