JEE Main & Advanced Mathematics Definite Integration Question Bank Summation of series by Definite Integration, Gamma function, Leibnitz's rule

  • question_answer
    \[\int_{0}^{\infty }{{{e}^{-2x}}(\sin 2x+\cos 2x)\,dx=}\]

    A)                 1             

    B)                 0

    C)                 \[\frac{1}{2}\]   

    D)                 \[\infty \]

    Correct Answer: C

    Solution :

                       \[\int_{0}^{\infty }{{{e}^{-2x}}(\sin 2x+\cos 2x)dx}\]                    \[=\left[ -{{e}^{-x}}\frac{\cos 2x}{2} \right]_{0}^{\infty }-\int_{0}^{\infty }{\left( -2{{e}^{-2x}} \right)\,}\left( \frac{-\cos 2x}{2} \right)\text{ }dx\]                           \[+\int_{0}^{\infty }{{{e}^{-2x}}\cos 2x\,dx}\]                                 \[=\frac{1}{2}\].


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