Manipal Engineering Manipal Engineering Solved Paper-2012

  • question_answer
    If\[\int{\frac{{{2}^{x}}}{\sqrt{1-{{4}^{x}}}}dx=k{{\sin }^{-1}}({{2}^{x}})+C}\], then\[k\]is equal to

    A) \[\log 2\]                            

    B) \[\frac{1}{2}\log 2\]

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

    D)        \[\frac{1}{\log 2}\]

    Correct Answer: D

    Solution :

    Let            \[I=\int{\frac{{{2}^{x}}}{\sqrt{1-{{4}^{x}}}}dx}\] Let          \[{{2}^{x}}=t\] \[\Rightarrow \]               \[{{2}^{x}}\log 2\,\,dx=dt\] \[\therefore \]  \[I=\frac{1}{\log 2}\int{\frac{1}{\sqrt{1-{{t}^{{}}}}}dt}\]                    \[=\frac{1}{\log 2}{{\sin }^{-1}}(t)+C\]                    \[=\frac{1}{\log 2}{{\sin }^{-1}}({{2}^{x}})+C\] But         \[I=k{{\sin }^{-1}}({{2}^{x}})+C\] \[\Rightarrow \]               \[k=\frac{1}{\log 2}\]


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