Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Calculus

Question:

In the interval [2, 5], the function $x^2-6 x+9$

A. is strictly increasing
B. is strictly decreasing
C. has absolute minima at x = 2
D. has absolute maxima at x = 5
E. never attains a negative value.

Choose the correct answer from the options given below:

Options:

D, E only

A, C, D only

A, E only

B, C, D only

Correct Answer:

D, E only

Explanation:

The correct answer is Option (1) → D, E only

$f(x)=x^2-6x+9=(x-3)^2$

$f'(x)=2(x-3)$

$f'(x)<0 \text{ for } x<3,\;\; f'(x)>0 \text{ for } x>3$

$\text{Hence not strictly increasing or decreasing on } [2,5]$

$f(2)=1,\;\; f(3)=0,\;\; f(5)=4$

$\text{Minimum at } x=3,\;\; \text{maximum at } x=5$

$f(x)\ge 0 \text{ for all } x$

The correct statements are D and E.