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AP EAMCET · Maths · Functions

If a function \(f: \mathrm{R} \rightarrow \mathrm{R}\) is defined by \(f(x)=x^3-x\), then \(f\) is

  1. A one-one and onto
  2. B one-one but not onto
  3. C onto but not one-one
  4. D neither one-one nor onto
Verified Solution

Answer & Solution

Correct Answer

(C) onto but not one-one

Step-by-step Solution

Detailed explanation

Given \(f: \mathrm{R} \rightarrow \mathrm{R}\) such that \(f(x)=x^3-x=x(x-1)(x+1)\) \(\because f(1)=0=f(0)\). So, \(f(x)\) is not one-one Since, \(f(x)=x^3-x\) is a polynomial function So it is continuous on R and, If \(x \rightarrow \infty \Rightarrow f(x) \rightarrow \infty\)…