Q. If $f(x) = \frac{1 - x}{1 + x}(x \neq - 1)$, then $f^{- 1}(x)$ equals to
A) $f(x)$
B) $\frac{1}{f(x)}$
C) $- f(x)$
D) $- \frac{1}{f(x)}$
Explanation
(a)
Let $y = f(x) = \frac{1 - x}{1 + x}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \lbrack\because x \neq - 1\rbrack$
$\Rightarrow \ \ \ \ x = \frac{1 - y}{1 + y}$
$\therefore\ \ \ \ f^{- 1}(x) = \frac{1 - x}{1 + x} = f(x)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.