Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

If \(f\left(x+\frac{1}{x}\right)=x^3+\frac{1}{x^3}\) then \(f(\sqrt{3})\) is equal to

Options:

\(0\)

\(1\)

\(\sqrt{3}\)

\(3\sqrt{3}\)

Correct Answer:

\(0\)

Explanation:

$f\left(x+\frac{1}{x}\right)=\frac{1}{x^3}+x^3$

$=\left(x+\frac{1}{x}\right)^3-3\left(x+\frac{1}{x}\right)$

so $f(y)=y^3-3y$

at $y=\sqrt{3}$

$f(\sqrt{3})={\sqrt{3}}^2-3\sqrt{3}=0$