Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

The function $f(x)=\frac{x^4}{4}-\frac{x^2}{2}$ has

Options:

2 points of local maxima

2 points of local minima and one point of local maxima

1 point of local minima and 2 points of local maximum

1 point of local maxima and 1 point of local minima

Correct Answer:

2 points of local minima and one point of local maxima

Explanation:

The correct answer is Option (2) → 2 points of local minima and one point of local maxima

$f(x)=\frac{x^4}{4}-\frac{x^2}{2}$

$f'(x)=x^3-x=0$

$⇒x(x^2-1)=0$

$x=0,1,-1$

Using wavy curve method

Points of local minima ⇒ -1, 1

Points of local maxima ⇒ 0