JEE Main & Advanced Mathematics Definite Integration Question Bank Properties of Definite Integration

  • question_answer
    The value of \[I=\int_{\,0}^{\,1}{\,x\,\left| x-\frac{1}{2} \right|\,dx}\] is                               [UPSEAT 2003]

    A)                 1/3        

    B)                 1/4

    C)                 1/8        

    D)                 None of these

    Correct Answer: C

    Solution :

               \[I=\int_{0}^{1}{x\,\left| \,x-\frac{1}{2}\, \right|\,dx}\]\[=-\int_{0}^{1/2}{x\left( x-\frac{1}{2} \right)+\int_{1/2}^{1}{x\left( x-\frac{1}{2} \right)}\,dx}\]         \[=\int_{0}^{1/2}{\left( \frac{1}{2}x-{{x}^{2}} \right)\,dx+\int_{1/2}^{1}{\left( {{x}^{2}}-\frac{1}{2}x \right)\,dx}}\]              \[=\left( \frac{{{x}^{2}}}{4}-\frac{{{x}^{3}}}{3} \right)_{0}^{1/2}+\left( \frac{{{x}^{3}}}{3}-\frac{{{x}^{2}}}{4} \right)_{1/2}^{1}\]                                   \[=\left( \frac{1}{16}-\frac{1}{24} \right)+\left( \frac{1}{3}-\frac{1}{4}+\frac{1}{16}-\frac{1}{24} \right)=\frac{1}{8}.\]


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