Manipal Engineering Manipal Engineering Solved Paper-2013

  • question_answer
    The solution of the equation \[\frac{dy}{dx}=\frac{x(2\log x+1)}{\sin y+y\cos y}\]

    A) \[y\sin y={{x}^{2}}\log x+\frac{{{x}^{2}}}{y}+c\]

    B) \[y\cos y={{x}^{2}}(\log x+1)+c\]

    C) \[y\cos y={{x}^{2}}\log x+\frac{{{x}^{2}}}{2}+c\]

    D) \[y\sin y={{x}^{2}}\log x+c\]

    Correct Answer: D

    Solution :

    \[(y\cos y+\sin y)dy=(2x\log x+x)dx\]                 \[y\sin y-\int{\sin y\,\,dy}+\int{\sin y\,\,dy}\]                 \[={{x}^{2}}\log x-\int{{{x}^{2}}\cdot \frac{1}{x}dx+\int{x\,\,dx+c}}\] \[\therefore \]  \[y\sin y={{x}^{2}}\log x+c\]


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