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

  • question_answer
    The value of \[\sin \left( 2{{\tan }^{-1}}\left( \frac{1}{3} \right) \right)+\cos ({{\tan }^{-1}}2\sqrt{2})=\] [AMU 1999]

    A) \[\frac{16}{15}\]

    B) \[\frac{14}{15}\]

    C) \[\frac{12}{15}\]

    D) \[\frac{11}{15}\]

    Correct Answer: B

    Solution :

    \[\sin \left[ 2{{\tan }^{-1}}\left( \frac{1}{3} \right) \right]+\cos \,[{{\tan }^{-1}}(2\sqrt{2})]\] = \[\sin \left[ {{\tan }^{-1}}\frac{2/3}{1-1/9} \right]+\cos \,[{{\tan }^{-1}}(2\sqrt{2})]\]   \[=\sin [{{\tan }^{-1}}3/4]+\cos \,[{{\tan }^{-1}}2\sqrt{2}]\]   \[=\frac{3}{5}+\frac{1}{3}=\frac{14}{15}\].


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