JEE Main & Advanced Mathematics Functions Question Bank Functions

  • question_answer
    The inverse of the function \[\frac{{{10}^{x}}-{{10}^{-x}}}{{{10}^{x}}+{{10}^{-x}}}\] is      [RPET 2001]

    A)                    \[\frac{1}{2}{{\log }_{10}}\left( \frac{1+x}{1-x} \right)\]

    B)            \[\frac{1}{2}{{\log }_{10}}\left( \frac{1-x}{1+x} \right)\]

    C)                    \[\frac{1}{4}{{\log }_{10}}\left( \frac{2x}{2-x} \right)\]

    D)            None of these

    Correct Answer: A

    Solution :

               \[y=\frac{{{10}^{x}}-{{10}^{-x}}}{{{10}^{x}}+{{10}^{-x}}}\Rightarrow x=\frac{1}{2}{{\log }_{10}}\left( \frac{1+y}{1-y} \right)\]            Let \[y=f(x)\] Þ \[x=\pi ,\,\,f(\pi )=-\tan \frac{\pi }{4}=-1\]            Þ \[{{f}^{-1}}(y)=\frac{1}{2}{{\log }_{10}}\left( \frac{1+y}{1-y} \right)\] Þ \[g({{\sin }^{2}}x)=\,|\sin x|\].


You need to login to perform this action.
You will be redirected in 3 sec spinner