CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2010

  • question_answer
    \[\int_{0}^{1}{x{{(1-x)}^{3/2}}}dx\] is

    A) \[-\frac{2}{35}\]                               

    B) \[\frac{4}{35}\]

    C)   \[\frac{24}{35}\]                                                

    D) \[-\frac{8}{35}\]

    Correct Answer: B

    Solution :

    \[\int_{0}^{1}{x}{{(1-x)}^{3/2}}dx\] \[={{\int_{0}^{1}{x}}^{(2-1)}}{{(1-x)}^{5/2-1}}dx\] \[=B(2,5/2)\left\{ \begin{matrix}    \because B(m,n)-\int_{0}^{1}{{{x}^{m-1}}{{(1-x)}^{n-1}}dx}  \\    \because B(m,n)=\frac{\Gamma m\Gamma n}{\Gamma (m+n)}  \\ \end{matrix} \right.\] \[=\frac{\Gamma 2\Gamma 5/2}{\Gamma (2+5/2)}\] \[=\frac{1.3/2.1/2\Gamma 1/2}{\Gamma 9/2}\]                \[(\because \Gamma 1/2=\sqrt{\pi })\] \[=\frac{3/4.\sqrt{\pi }}{7/2.5/2.3/2.1/2\sqrt{\pi }}=\frac{4}{35}\]


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