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TS EAMCET · Maths · Functions

Let \(f: R \rightarrow R\) and \(g: R \rightarrow R\) be the functions defined by \(f(x)=\frac{x}{1+x^2}\), \(x \in R, g(x)=\frac{x^2}{1+x^2}, x \in R\) Then, the correct statement (s) among the following is/are : (a) both \(f . g\) are one-one (b) both \(f . g\) are onto (c) both \(f . g\) are not one-one as well as not onto (d) \(f\) and \(g\) are onto but not one-one

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

Answer & Solution

Correct Answer

(D) C

Step-by-step Solution

Detailed explanation

We have, \[ \begin{aligned} & f(x)=\frac{x}{1+x^2}, x \in R \\ & g(x)=\frac{x^2}{1+x^2}, x \in R \\ & f^{\prime}(x)=\frac{1+x^2-2 x^2}{\left(1+x^2\right)^2} \\ & f^{\prime}(x)=\frac{1-x^2}{\left(1+x^2\right)^2} \end{aligned} \] Clearly \(f(x)\) is not monotonic.…