KVPY Sample Paper KVPY Stream-SX Model Paper-30

  • question_answer
    If \[A=2{{\tan }^{-1}}(2\sqrt{2}-1)\], and \[B={{\sin }^{-1}}\left( \frac{1}{3} \right)+{{\sin }^{-1}}\left( \frac{3}{5} \right)\] then

    A) \[A>B\]

    B) \[A=B\]

    C) \[A<B\]            

    D) none of these

    Correct Answer: A

    Solution :

    \[A=2{{\tan }^{-1}}(2\sqrt{2}-1)>2ta{{n}^{-1}}\sqrt{3}=\frac{2\pi }{3}\] \[\Rightarrow A>\frac{2\pi }{3}.\,\,\,Now\frac{1}{3}<\frac{\sqrt{3}}{2}\]
    \[={{\sin }^{-1}}(1/3)<si{{n}^{-1}}\left( \frac{\sqrt{3}}{2} \right)=\frac{\pi }{3};{{\sin }^{-1}}\left( \frac{3}{5} \right)<{{\sin }^{-1}}\left( \frac{\sqrt{3}}{2} \right)=\frac{\pi }{3}.\]\[B={{\sin }^{-1}}\left( \frac{1}{3} \right)+{{\sin }^{-1}}\left( \frac{3}{5} \right)<\frac{\pi }{3}+\frac{\pi }{3}=\frac{2\pi }{3}\]
    Now \[A>\frac{2\pi }{3},\,\,B<\frac{2\pi }{3}.\,\,\therefore A>B.\]


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