JEE Main & Advanced Sample Paper JEE Main - Mock Test - 42

  • question_answer
    The equation \[si{{n}^{-1}}x-co{{s}^{-1}}x=co{{s}^{-1}}\left( \frac{\sqrt{3}}{2} \right)\] has -

    A) No solution      

    B)        Unique solution

    C) Infinite solution  

    D)        None of these

    Correct Answer: B

    Solution :

    [b] \[{{\sin }^{-1}}x-co{{s}^{-1}}x=co{{s}^{\text{-}1}}\left( \frac{\sqrt{3}}{2} \right)\] \[\Rightarrow \frac{\pi }{2}-co{{s}^{-1}}x-co{{s}^{\text{-}1}}x={{\cos }^{-1}}\left( \frac{\sqrt{3}}{2} \right)\] \[\Rightarrow \frac{\pi }{2}-\frac{\pi }{6}=2co{{s}^{\text{-}1}}x\] \[\Rightarrow \frac{\pi }{3}=2co{{s}^{\text{-}1}}x\] \[\Rightarrow co{{s}^{\text{-}1}}x=\frac{\pi }{6}\] \[\Rightarrow x=\frac{\sqrt{3}}{2}\] i.e. unique solution


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