JEE Main & Advanced Mathematics Indefinite Integrals Question Bank Self Evaluation Test - Integrals

  • question_answer
    \[\int\limits_{0}^{2\pi }{\log \left( \frac{a+b\sec x}{a-b\sec x} \right)}dx=\]

    A) 0

    B) \[\pi /2\]

    C) \[\frac{\pi (a+b)}{a-b}\]

    D) \[\frac{\pi }{2}({{a}^{2}}-{{b}^{2}})\]

    Correct Answer: A

    Solution :

    [a] \[\int\limits_{0}^{2\pi }{\log \left( \frac{a+b\sec x}{a-b\sec x} \right)dx}\] \[=2\int\limits_{0}^{\pi }{\log \left( \frac{a+b\sec x}{a-b\sec x} \right)dx}\]  \[=2\int\limits_{0}^{\pi }{\log (a+b\,\,\sec \,\,x)dx-2\int\limits_{0}^{\pi }{\log (a-b\sec (\pi -x))dx}}\] \[=2\int\limits_{0}^{\pi }{\log (a+b\,\,\sec \,\,x)dx-2\int\limits_{0}^{\pi }{\log (a+b\sec \,x)dx=0}}\]


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