Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Definite Integration

Question:

Let f(x) be a function defined by $f(x)=\int_1^xx(x^2-3x+2)dx,\,1≤x≤3$. Then the range of f(x) is:

Options:

[0, 2]

$[-\frac{1}{4},4]$

$[-\frac{1}{4},2]$

None of these

Correct Answer:

$[-\frac{1}{4},2]$

Explanation:

f'(x) = x(x - 1)(x - 2)

$f(2)=-\frac{1}{4}$ f(3) = 2  f(1) = 0

$f_{min}=min[f(1),f(2),f(3)]=-\frac{1}{4}\,∀\, x∈[1,3]$

$f_{max}=max[f(1),f(3)]=2\,∀\, x∈[1,3]$; Range = $[-\frac{1}{4},2]$