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Math Help - integral by time, can you help me?

  1. #1
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    Exclamation integral by time, can you help me?

    hi ,

    i want to integrate this, by time:

     \int\dot{y}^2dt

    how can this integrate short?

    and can you say me some links about partial differential equations(like hamilton-jacobi in physic, non-linear etc..) i think some text books, or online tutorials, by that themes, and theme "integrate,derive by time."

    thanks for you help,
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  2. #2
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    \int y'y' dt  = \int y'y'+yy'-yy' dt = \int y'(y+1) dt - \int yy'dt

    In \int y'(y+1) dt let u=y+1
    In \int yy'dt let u=y.
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  3. #3
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    i dont understand the following step (maybe its false?),

    Quote Originally Posted by ThePerfectHacker View Post
    \int y'y'+yy'-yy' dt = \int y'(y+1) dt - \int yy'dt
    could you write it a bit detailed?

    but thanks for your help,
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  4. #4
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    I added an subtracted the same quantity. Thereby not chaning the value of the integral at all.
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