Question
Question: Range of \(f ( x ) = \sqrt { \ell n ( \cos ( \sin x ) ) }\) is...
Range of f(x)=ℓn(cos(sinx)) is
A
[0, ln (cosec 1))
B
[0, ln (sec 1))
C
(ln (cosec 1)), ln (sec 1))
D
{0}
Answer
{0}
Explanation
Solution
First of all we must ensure that ln (cos(sinx)) ≥ 0
⇒ cos(sinx) ≥ 1
⇒ cos(sinx) = 1 ⇒ ln cos(sinx) = 0
∀ x ∈ domain. Thus range is {0}.