Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Applications of Derivatives

Question:

The function $f(x)=2x^3-3x^2-12x+4$ has :

Options:

two points of local minimum

two points of local maximum

one maximum and one minima

no maxima or minima

Correct Answer:

one maximum and one minima

Explanation:

The correct answer is Option (3) → one maximum and one minima

$f(x)=2x^3-3x^2-12x+4$

$f'(x)=6x^2-6x-12=0$

$x^2-x-2=0$

$x=2,-1$

$f''(x)=12x$ so $f''(2)=24>0$

$f''(-1)=-12$

2 → point of local minima

-1 → point of local maxima