JEE Main & Advanced Mathematics Inverse Trigonometric Functions Question Bank Inverse trigonometric functions

  • question_answer
    If \[2{{\cos }^{-1}}\sqrt{\frac{1+x}{2}}=\frac{\pi }{2},\]then \[x=\]

    A) 1

    B) 0

    C) -1/2

    D) 1/2

    Correct Answer: B

    Solution :

    Given equation is \[2{{\cos }^{-1}}\sqrt{\left( \frac{1+x}{2} \right)}=\frac{\pi }{2}\] Þ \[{{\cos }^{-1}}\sqrt{\left( \frac{1+x}{2} \right)}=\frac{\pi }{4}\Rightarrow \cos \frac{\pi }{4}=\frac{\sqrt{1+x}}{\sqrt{2}}\] Þ \[\frac{1}{\sqrt{2}}=\frac{\sqrt{1+x}}{\sqrt{2}}\Rightarrow 1=\sqrt{1+x}\Rightarrow x=0\].


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