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Math Help - line integral very urgent please help

  1. #1
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    line integral very urgent please help

    Find line integral F(x,y) .dr
    where C is the curve given by
    r(t)=(t^2 -2)i+((t-1)+t(t-2)cos(t))j 0<=t<=2

    and
    f(x,y) = (xy^2+2x)i+(x^2y +y+1)j
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    Last edited by bobby77; December 8th 2005 at 10:48 PM.
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by bobby77
    Find line integral F(x,y) .dr
    where C is the curve given by
    r(t)=(t^2 -2)i+((t-1)+t(t-2)cos(t))j 0<=t<=2

    and
    f(x,y) = (xy^2+2x)i+(x^2y +y+1)j
    You need to know that:

    \vec r(t)\ =\ x(t).i\ +\ y(t).j

    so:

    x(t)=t^2-2
    y(t)=(t-1)+t(t-2)cos(t).

    Then

    \int_C{\vec F(x,y)} \cdot d \vec r\ =\ \int_0^2{\vec F(x(t),y(t))} \cdot \frac{d \vec r}{dt}\ dt\

    which I trust you I can leave to you

    (by the way the value of the integral is 2 )

    RonL
    Last edited by CaptainBlack; December 9th 2005 at 05:45 AM.
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