N2013 P1 Q5 [Modified]

N2013 P1 Q5 [Modified]

Past Year National Exams
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It is given that

\(\mathrm{f}(x)=\left\{ \begin{array}{*{35}{l}} \sqrt{1-\frac{{{x}^{2}}}{{{a}^{2}}}} & \mathrm{for }-a\le x\le a, \\ 0 & \mathrm{for }a < x < 2a,\end{array}\right.\)

and that \(\mathrm{f}(x+3a)=\mathrm{f}(x)\) for all real values of \(x\), where \(a\) is a real constant.

  1. Sketch the graph of \(y=\mathrm{f}(x)\) for \(-4a\le x\le 6a\).
  2. State the range of \(\mathrm{f}\).
  3. Explain whether \({{\mathrm{f}}^{-1}}\) exists for \(-a\le x\le 2a\).

Video Solution:

Default solution

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Answer:(ii) \({{\mathrm{R}}_{\mathrm{f}}}=\left[ 0,1 \right]\) (iii) The line \(y=\frac{1}{2}\) cuts \(\mathrm{f}\) twice for \(-a\le x\le 2a\), thus \(\mathrm{f}\) is not a one-one for \(-a\le x\le 2a\). Hence \({{\mathrm{f}}^{-1}}\) doesn’t exist for \(-a\le x\le 2a\).

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