If $f(x)=\left(p-x^n\right)^{1 / n}, p>0$ and $n$ is a positive integer, then $f[f(x)]$ is equal to

If $f(x)=\left(p-x^n\right)^{1 / n}, p>0$ and $n$ is a positive integer, then $f[f(x)]$ is equal to
  1. $x$
  2. $x^n$
  3. $p^{1 / n}$
  4. $p-x^n$

Solution

Given, $\quad f(x)=\left(p-x^n\right)^{1 / n}, p>0$ Now, $ \begin{aligned} f[f(x)] & =f\left[\left(p-x^n\right)^{1 / n}\right] \\ & =\left\{p-\left(p-x^n\right)^{1 / n \times n}\right\}^{1 / n} \\ & =\left(x^n\right)^{1 / n}=x \end{aligned} $

Asked in: AP EAMCET 2013

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