Question

If the function f(x) = cos |x| – 2ax + b increases along the entire number scale, then

A. a = b

B. a = \(\frac{1}{2}\text{b}\)

C. a ≤ \(-\frac{1}{2}\)

D. a > \(-\frac{3}{2}\)

Answer 1

Correct answer is C.

Formula:-

(i) The necessary and sufficient condition for differentiable function defined on (a, b) to be strictly increasing on (a, b) is that f’(x) > 0 for all x ∈ (a, b)

Given:-