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Homework Help: Arc Length

  1. Sep 20, 2010 #1
    1. The problem statement, all variables and given/known data
    Find the arclength of the curve r(t)=(10t^2,2*sqrt(10)*t, ln t)
    for 1<=t<=8

    2. Relevant equations



    3. The attempt at a solution
    i took the derivative of each component of vector r

    20t,2sqrt(10),1/t
    then i square each term and square root it

    int sqrt( 400t + 40 + 1/t^2)dt

    i cant integrate this to find out the length tho.
     
  2. jcsd
  3. Sep 21, 2010 #2

    Mark44

    Staff: Mentor

    400t should be 400t2.
    If you make the change above, you'll have a perfect square that you can take the square root of.
     
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