JEE Main & Advanced Mathematics Definite Integration Question Bank Fundamental definite integration, Definite integration by substitution

  • question_answer
    The value of the integral \[\int_{0}^{\log 5}{\frac{{{e}^{x}}\sqrt{{{e}^{x}}-1}}{{{e}^{x}}+3}}\,dx=\]

    A)                 \[3+2\pi \]          

    B)                 \[4-\pi \]

    C)                 \[2+\pi \]            

    D)                 None of these

    Correct Answer: B

    Solution :

               Put \[{{e}^{x}}-1={{t}^{2}}\Rightarrow {{e}^{x}}dx=2t\,dt\]            Also as \[x=0\]to \[\log 5,t=0\]to 2            Therefore, \[\int_{0}^{\log 5}{\frac{{{e}^{x}}\sqrt{{{e}^{x}}-1}}{{{e}^{x}}+3}}dx=\int_{0}^{2}{\frac{2{{t}^{2}}}{{{t}^{2}}+4}dt}\]                           \[=2\left[ \int_{0}^{2}{1dt-4\int_{0}^{2}{\frac{dt}{{{t}^{2}}+4}}} \right]=4-\pi \].


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