JEE Main & Advanced AIEEE Solved Paper-2008

  • question_answer
    Let \[I=\int\limits_{0}^{1}{\frac{\sin x}{\sqrt{x}}dx}\] and \[J=\int\limits_{0}^{1}{\frac{\cos x}{\sqrt{x}}dx}\]. Then which one of the following is true?       AIEEE  Solved  Paper-2007

    A) \[I<\frac{2}{3}\] and \[J<2\]

    B)        \[I>\frac{2}{3}\] and \[J<2\]

    C)                        \[I>\frac{2}{3}\] and \[J>2\]       

    D) \[I<\frac{2}{3}\] and \[J>2\]

    Correct Answer: D

    Solution :

                    We know that \[\frac{\sin x}{x}<1\], when\[x\in \left( 0,1 \right)\Rightarrow \frac{\sin x}{\sqrt{x}}<\sqrt{x}\Rightarrow \int\limits_{0}^{1}{\frac{\sin x}{\sqrt{x}}<\frac{2}{3}}\] Again \[\frac{\cos x}{\sqrt{x}}<\frac{1}{\sqrt{x}}\] when \[x\in \left( 0,1 \right)\Rightarrow \int\limits_{0}^{1}{\frac{\cos x}{\sqrt{x}}<2}\]


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