If $R$ is the set of all real numbers and $f: R-\{2\} \rightarrow R$ is defined by $f(x)=\frac{2+x}{2-x}$…

If $R$ is the set of all real numbers and $f: R-\{2\} \rightarrow R$ is defined by $f(x)=\frac{2+x}{2-x}$ for $x \in R-\{2\}$
  1. $R-\{-2\}$
  2. $R$
  3. $R-\{1\}$
  4. $R-\{-1\}$

Solution

Let $y=f(x)=\frac{2+x}{2-x}$ $ \begin{aligned} & \Rightarrow \quad 2 y-x y=2+x \\ & \Rightarrow \quad x(1+y)=2 y-2 \\ & \Rightarrow \quad x=\frac{2(y-1)}{1+y}, y \neq-1 \end{aligned} $ $\therefore$ Domain of $y$ is $R-\{-1\}$. Hence, range of $f(x)$ is $R-\{-1\}$

Asked in: AP EAMCET 2014

Practice more Functions questions on Aicharya