Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Determinants

Question:

The value of $x$, for which the function $f(x)=x(x-2)$ attains its minimum value, is:

Options:

$\frac{1}{2}$

1

2

0

Correct Answer:

1

Explanation:

$f(x) =x(x-2)$

$=x^2-2 x$

so $f'(x)=2 x-2$

differential w.r.t x

finding critical points as f'(x) = 0

⇒ 2x - 2 = 0

⇒ x = 1

f''(x) = 2 

differentiating f'(x) w.r.t x

for f''(1) = 2 > 0

⇒ 1 is point of minima