Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

Let $f: R-\left\{\frac{3}{5}\right\} → R$ be defined by $f(x)=\frac{3 x+2}{5 x-3}$, then

Options:

$f^{-1}(x)=f(x)$

$f^{-1}(x)=-f(x)$

$(fof)(x)=x^2$

$f^{-1}|x|=\frac{1}{19} f(x)$

Correct Answer:

$f^{-1}(x)=f(x)$

Explanation:

The correct answer is Option (1) → $f^{-1}(x)=f(x)$

$y=\frac{3x+2}{5x-3}⇒5xy-3y=3x+2$

So $5xy-3x=3y+2$

$x=\frac{3y+2}{5y-3}$

So $f^{-1}(x)=\frac{3x+2}{5x-3}$

$⇒f^{-1}(x)=f(x)$