Which of the following functions has a local minima at $x = 0$? (A) $f(x)=x^3$ Choose the correct answer from the options given below. |
(A), (B) and (C) only (D) only (B), (C) and (D) only (B) and (C) only |
(B) and (C) only |
The correct answer is Option (4) → (B) and (C) only (A) $f(x)=x^{3}$ → $f'(x)=3x^{2}$, $f''(x)=6x$, $f''(0)=0$ → point of inflection, no minimum. (B) $f(x)=|x|$ → decreases for $x<0$, increases for $x>0$ → local minimum at $x=0$. (C) $f(x)=x^{2}$ → $f'(x)=2x$, $f'(0)=0$, $f''(0)=2>0$ → local minimum at $x=0$. (D) $f(x)=x-2$ → linear function, no extremum. Functions having local minimum at $x=0$ are (B) and (C). |