Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

The minimum value that $f(x)=4 x^2-4 x+11+\sin 3 \pi x$ attains, is

Options:

12

10

8

none of these

Correct Answer:

none of these

Explanation:

We have,

$f(x)=4 x^2-4 x+11+\sin 3 \pi x$

$\Rightarrow f(x)=4\left(x-\frac{1}{2}\right)^2+10+\sin 3 \pi x$

We observe that $4\left(x-\frac{1}{2}\right)^2$ takes its least value 0 at $x=\frac{1}{2}$ and at this point $\sin 3 \pi x$ also takes its least value -1 . Hence, f(x) attains its least value 9 at $x=\frac{1}{2}$.