Question

The value of b for which the function f(x) = x + cos x + b is strictly decreasing over R is:

Options

• b < 1

• No value of b exists

• b ≤ 1

• b ≥ 1

Answer 1

No value of b exists

Explanation:

f'(x) = 1 − sin x ⇒ f'(x) ≥ 0 ∀ x ∈ R

No value of b exists