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Homework Help: The equation for length of a curve: what are the integral ends?

  1. Mar 2, 2012 #1
    1. The problem statement, all variables and given/known data

    The given curve is r(t) = <t2, 2t, -3>

    Write an equation for the length of the curve from <0,0,-3> to <1, 2, -3>

    2. The attempt at a solution

    I take the derivative of r(t) for r'(t), then plug it into the length formula.

    L = ∫ of √( (2t)2 + 22 )

    For the Integral, I put from 0 to 1, because in the original equation, the x component t2 = 1 when t is 1, and the y component 2t = 2 when t is 1.

    Am I doing something wrong? o_o
  2. jcsd
  3. Mar 2, 2012 #2


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    Seems ok to me. Why do you think you are doing something wrong?
  4. Mar 2, 2012 #3
    Ah ok. The notes never fully explained it so I was doing it by instinct mostly. xD

  5. Apr 15, 2012 #4
    Last edited: Apr 15, 2012
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