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

  • question_answer
    \[\int_{{}}^{{}}{\log x(\log x+2)\ dx=}\]

    A)                 \[x{{(\log x)}^{2}}+c\]

    B)                 \[x{{(1+\log x)}^{2}}+c\]

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

    D)                 None of these

    Correct Answer: A

    Solution :

                    \[I=\int_{{}}^{{}}{\log x(\log x+2)\,dx}\]                 Put \[\log x=t\Rightarrow {{e}^{t}}=x\Rightarrow {{e}^{t}}dt=dx,\] then                 \[I=\int_{{}}^{{}}{t(t+2){{e}^{t}}dt}={{t}^{2}}.\,{{e}^{t}}+c=x{{(\log x)}^{2}}+c.\]


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