JEE Main & Advanced Mathematics Indefinite Integrals Question Bank Integration by Substitution

  • question_answer
    \[\int_{{}}^{{}}{\frac{10{{x}^{9}}+{{10}^{x}}{{\log }_{e}}10}{{{10}^{x}}+{{x}^{10}}}}\ dx=\] [MNR 1979]

    A)            \[-\frac{1}{2}\frac{1}{{{({{10}^{x}}+{{x}^{10}})}^{2}}}+c\]

    B)            \[\log ({{10}^{x}}+{{x}^{10}})+c\]

    C)            \[\frac{1}{2}\frac{1}{{{({{10}^{x}}+{{x}^{10}})}^{2}}}+c\]

    D)            None of these

    Correct Answer: B

    Solution :

                       Put \[{{x}^{10}}+{{10}^{x}}=t\Rightarrow (10{{x}^{9}}+{{10}^{x}}{{\log }_{e}}10)\,dx=dt,\]            then \[\int_{{}}^{{}}{\frac{10{{x}^{9}}+{{10}^{x}}{{\log }_{e}}10}{{{10}^{x}}+{{x}^{10}}}\,dx}=\int_{{}}^{{}}{\frac{1}{t}\,dt=\log t+c}\]                                                       \[=\log ({{x}^{10}}+{{10}^{x}})+c.\]


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