The function \(f(x) = \log(\log x)\), \(x \gt 1\), is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → strictly increasing on \((1, \infty)\)
By the chain rule,
\( \displaystyle f'(x) = \frac{1}{\log x} \cdot \frac{1}{x} = \frac{1}{x\log x} \)
For x > 1, both x and log x are positive, so
\(f'(x) \gt 0\) for every \(x \gt 1\)
The derivative never changes sign, so f is strictly increasing on the whole of \((1, \infty)\); nothing special happens at x = e.