Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Applications of Derivatives

Question:

What is the minimum value of y = \( { x }^{ 2 } -4x\)?

Options:

-4

-8

-2

0

Correct Answer:

-4

Explanation:

The correct answer is Option (1) → -4

$y=x^2-4x$

for critical points, $f'(c)=0$

$⇒2c-4=0$

$⇒c=\frac{4}{2}=2$

and,

$f''(c)=2>0$

∴ At $x=2$, $f(x)=y=x^2-4x$ attains it's minimum value.