JEE Main & Advanced Mathematics Definite Integration Question Bank Properties of Definite Integration

  • question_answer
    The value of \[\int_{0}^{\pi /2}{\log \,\left( \frac{4+3\sin x}{4+3\cos x} \right)}\,dx\] is

    A)                 2             

    B)                 \[\frac{3}{4}\]

    C)                 0             

    D)                 None of these

    Correct Answer: C

    Solution :

               Let \[I=\int_{0}^{\pi /2}{\log \left( \frac{4+3\sin x}{4+3\cos x} \right)}\,dx.\]                    Then, \[I=\int_{0}^{\pi /2}{\log \left( \frac{4+3\cos x}{4+3\sin x} \right)}\,dx\],                              \[\left[ \because \int_{0}^{\pi /2}{f(x)dx=\int_{0}^{\pi /2}{f\left( \frac{\pi }{2}-x \right)\,dx}} \right]\]                    Þ \[I=-\int_{0}^{\pi /2}{\log \left( \frac{4+3\sin x}{4+3\cos x} \right)\,dx=-I}\]                                 Þ \[2I=0\Rightarrow I=0\].


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