JEE Main & Advanced Mathematics Inverse Trigonometric Functions Question Bank Self Evaluation Test - Inverse Trigonometric Functions

  • question_answer
    Let \[x\in (0,1).\]The set of all x such that \[{{\sin }^{-1}}x>{{\cos }^{-1}}x,\] is the interval:

    A) \[\left( \frac{1}{2},\frac{1}{\sqrt{2}} \right)\]

    B) \[\left( \frac{1}{\sqrt{2}},1 \right)\]

    C) \[(0,1)\]

    D) \[\left( 0,\frac{\sqrt{3}}{2} \right)\]

    Correct Answer: B

    Solution :

    [b] Given \[{{\sin }^{-1}}x>{{\cos }^{-1}}x\]where \[x\in (0,1)\] \[\Rightarrow {{\sin }^{-1}}x>\frac{\pi }{2}-{{\sin }^{-1}}x\Rightarrow 2{{\sin }^{-1}}x>\frac{\pi }{2}\] \[\Rightarrow {{\sin }^{-1}}x>\frac{\pi }{4}\Rightarrow x>\sin \frac{\pi }{4}\Rightarrow x>\frac{1}{\sqrt{2}}\] Maximum value of \[{{\sin }^{-1}}x\] is \[\frac{\pi }{2}\] So, maximum value of x is 1, so, \[x\in \left( \frac{1}{\sqrt{2}},1 \right).\]


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