MCQ
The function $f(x)=2 x+3(x)^{\frac{2}{3}}, x \in R,$ has
  • A
    exactly one point of local minima and no point of local maxima
  • B
    exactly one point of local maxima and no point of local minima
  • C
    exactly one point of local maxima and exactly one point of local minima
  • D
    exactly two points of local maxima and exactly one point of local minima

Answer

$f(x)=2 x+3(x)^{\frac{2}{3}}$
$f^{\prime}(x)=2+2 x^{\frac{-1}{3}}$
$=2\left(1+\frac{1}{x^{\frac{1}{3}}}\right)$
$=2\left(\frac{x^{\frac{1}{3}}+1}{x^{\frac{1}{3}}}\right)$
Image
So, maxima $(M)$ at $x=-1 \ \operatorname{minima}(m)$ at $x=0$

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