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TS EAMCET · Maths · Functions

The function \(f: R \rightarrow R\) is defined by \(f(x)=3^{-x}\). Observe the following statements of it I. \(f\) is one-one II. \(f\) is onto III. \(f\) is a decreasing function Out of these, true statement are

  1. A Only I, II
  2. B Only II,III
  3. C Only I,III
  4. D I,II,III
Verified Solution

Answer & Solution

Correct Answer

(A) Only I, II

Step-by-step Solution

Detailed explanation

Since, \(f: R \rightarrow R\) such that \(f(x)=3^{-x}\). Let \(y_1\) and \(y_2\) be two elements of \(f(x)\) such that \[ \begin{aligned} & y_1=y_2 \\ & \Rightarrow \quad 3^{-x_1}=3^{-x_2} \Rightarrow x_1=x_2 \\ & \end{aligned} \] Since, if two images are equal, then their…