Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

Let \(f(x)=\left\{\begin{array}3-x, & 0≤x<1 \\ x^2+lnb, & x ≥ 0\end{array}\right.\). Then the set of values of b for which f(x) has the least value at x = 1, is given by

Options:

(0, 1]

( -e, 0]

(-∞, e)

none of these.

Correct Answer:

(-∞, e)

Explanation:

$\underset{x→1^-}{lim}f(x)≥f(1)⇒2≥1+lnb≤1⇒b≤e$

Hence (C) is the correct answer.