JEE Main & Advanced JEE Main Paper (Held On 19 May 2012)

  • question_answer
    A value of \[{{\tan }^{-1}}\left( \sin \left( {{\cos }^{-1}}\left( \sqrt{\frac{2}{3}} \right) \right) \right)\]is       JEE Main  Online Paper (Held On 19  May  2012)

    A) \[\frac{\pi }{4}\]                                              

    B)                        \[\frac{\pi }{2}\]

    C)                        \[\frac{\pi }{3}\]                                              

    D)                        \[\frac{\pi }{6}\]

    Correct Answer: D

    Solution :

                    Consider\[{{\tan }^{-1}}\left[ \sin \left( {{\cos }^{-1}}\sqrt{\frac{2}{3}} \right) \right]\] Let\[{{\cos }^{-1}}\sqrt{\frac{2}{3}}=\theta \Rightarrow \cos \theta =\sqrt{\frac{2}{3}}\] \[\Rightarrow \]\[\sin \theta \sqrt{1-{{\cos }^{2}}\theta }=\sqrt{1-\frac{2}{3}}=\sqrt{\frac{1}{3}}\] \[\therefore \]\[\left[ \sin \left( {{\cos }^{-1}}\sqrt{\frac{2}{3}} \right) \right]={{\tan }^{-1}}[\sin \theta ]\] \[=\left[ \sqrt{\frac{1}{3}} \right]={{\tan }^{-1}}\left( \frac{1}{\sqrt{3}} \right)\]\[=\frac{\pi }{6}\]


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