For the function \(f(x) = (x - 2)^3 + 1\), \(x \in R\), the point \(x = 2\) is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → neither a point of local maximum nor a point of local minimum
Differentiating:
\(f'(x) = 3(x - 2)^2\)
So f’(2) = 0 and x = 2 is a critical point. Here \(f''(x) = 6(x - 2)\) gives f’’(2) = 0, so the second derivative test does not decide. By the first derivative test:
\(x \lt 2\): \(f'(x) = 3(x - 2)^2 \gt 0\)
\(x \gt 2\): \(f'(x) = 3(x - 2)^2 \gt 0\)
The sign of f’(x) does not change at x = 2; f is increasing on both sides. So x = 2 is neither a point of local maximum nor a point of local minimum (it is a point of inflection).