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TS EAMCET · Maths · Functions

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. A \(R-\{-2\}\)
  2. B \(R\)
  3. C \(R-\{1\}\)
  4. D \(R-\{-1\}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(R-\{-1\}\)

Step-by-step Solution

Detailed explanation

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 \(R-\{-1\}\).