JEE Main & Advanced JEE Main Solved Paper-2014

  • question_answer
    The integral\[\int_{{}}^{{}}{\left( 1+x-\frac{1}{x} \right)}{{e}^{x+\frac{1}{x}}}dx\]is equal to   JEE Main  Solved  Paper-2014

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

    B) \[x{{e}^{x+\frac{1}{x}}}+c\]

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

    D) \[-x{{e}^{x+\frac{1}{x}}}+c\]

    Correct Answer: B

    Solution :

    \[\int_{{}}^{{}}{\left( 1+x-\frac{1}{x} \right){{e}^{x+\frac{1}{x}}}dx}\] Put\[x{{e}^{x+\frac{1}{x}}}=t\] \[x{{e}^{x+\frac{1}{x}}}\left\{ 1-\frac{1}{{{x}^{2}}} \right\}+{{e}^{x+\frac{1}{x}}}dx=dt\] \[\left\{ x\left( 1-\frac{1}{{{x}^{2}}} \right)+1 \right\}{{e}^{x+\frac{1}{x}}}dx=dt\] \[\left( 1+x-\frac{1}{x} \right){{e}^{x+\frac{1}{x}}}dx=dt\] \[=\int_{{}}^{{}}{dt=t+c=x\,{{e}^{x+\frac{1}{x}}}+C}\]


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