The number of critical points of the function $f(x)=(x-2)^{2 / 3}(2 x+1)$ is

The number of critical points of the function $f(x)=(x-2)^{2 / 3}(2 x+1)$ is
  1. 1
  2. 2
  3. 0
  4. 3

Solution

$\begin{aligned} & \mathrm{f}(\mathrm{x})=(\mathrm{x}-2)^{2 / 3}(2 \mathrm{x}+1) \\ & \mathrm{f}^{\prime}(\mathrm{x})=\frac{2}{3}(\mathrm{x}-2)^{-1 / 3}(2 \mathrm{x}+1)+(\mathrm{x}-2)^{2 / 3} \\ & \mathrm{f}^{\prime}(\mathrm{x})=2 \times \frac{(2 \mathrm{x}+1)+(\mathrm{x}-2)}{3(\mathrm{x}-2)^{1 / 3}} \\ & \frac{3 \mathrm{x}-1}{(\mathrm{x}-2)^{1 / 3}}=0\end{aligned}$ Critical points $\mathrm{x}=\frac{1}{3}$ and $\mathrm{x}=2$

Asked in: JEE Main 2024 (08 Apr Shift 1)

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