Manipal Engineering Manipal Engineering Solved Paper-2011

  • question_answer
    The value of\[\int_{0}^{\pi /2}{|\sin x-\cos x|}\,\,dx\]is

    A) \[0\]                                     

    B) \[2(\sqrt{2}-1)\]

    C) \[\sqrt{2}-1\]    

    D)        \[2(\sqrt{2}+1)\]

    Correct Answer: B

    Solution :

    \[\int_{0}^{\pi /2}{|\sin x-\cos x|dx}\]                 \[=\int_{0}^{\pi /4}{-(\sin x-\cos x)dx}\]                                     \[+\int_{\pi /4}^{\pi /2}{-(\sin x-\cos x)dx}\] \[=-[-\cos x-\sin x]_{0}^{\pi /4}\]                                                 \[+[-\cos x-\sin x]_{\pi /4}^{\pi /2}\] \[=-\left[ -\frac{1}{\sqrt{2}}-\frac{1}{\sqrt{2}}+1 \right]\]                                 \[+\left[ -0-1+\left( \frac{1}{\sqrt{2}}+\frac{1}{\sqrt{2}} \right) \right]\] \[=\sqrt{2}-1-1+\sqrt{2}\] \[=2(\sqrt{2}-1)\]


You need to login to perform this action.
You will be redirected in 3 sec spinner