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

  • question_answer
    The value of \[\int_{-1}^{1}{\frac{\sin x-{{x}^{2}}}{3-|x|}\,dx}\] is                            [Roorkee 1995]

    A)                 0             

    B)                 \[2\int_{0}^{1}{\frac{\sin x}{3-|x|}\,dx}\]

    C)                 \[2\int_{0}^{1}{\frac{-{{x}^{2}}}{3-|x|}}\,dx\]   

    D)                 \[2\int_{0}^{1}{\frac{\sin x-{{x}^{2}}}{3-|x|}\,dx}\]

    Correct Answer: C

    Solution :

                       \[I=\int_{-1}^{1}{\,\frac{\sin x-{{x}^{2}}}{3\,\,-|x|}\,}dx=\int_{-1}^{1}{\,\frac{\sin x}{3-|x|}}\,dx-\int_{-1}^{1}{\,\frac{{{x}^{2}}}{3-|x|}}\,dx\]            Here, \[f(x)=\frac{\sin x}{3-|x|}\] is an odd function but \[f(x)=\frac{{{x}^{2}}}{3-|x|}\] is an even function                      \[\therefore \,\,I=-\int_{-1}^{1}{\frac{{{x}^{2}}}{3-|x|}\,}dx=-2\int_{0}^{1}{\frac{{{x}^{2}}}{3-|x|}}\,dx\]\[=2\int_{0}^{1}{\frac{-{{x}^{2}}}{3-|x|}\,}dx\].


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