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Homework Help: Arc Length Integral Question

  1. Feb 3, 2009 #1
    1. The problem statement, all variables and given/known data
    Find the arc length of the equation [tex]y^2=4(x+4)^3[/tex] from [tex]x=0[/tex] to [tex]x=2[/tex]

    2. Relevant equations
    [tex]L=\int_{a}^{b}\sqrt{1+f'(x)}dx[/tex]


    3. The attempt at a solution
    [tex]L=\int_{0}^{2}\sqrt{1+9(x+4)}dx[/tex]
    which simplifies in to
    [tex]L=\int_{0}^{2}\sqrt{9x+37}dx[/tex]
    and i'm stuck there--how should i try to integrate that?
     
  2. jcsd
  3. Feb 3, 2009 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Substitute u=9x+37?
     
  4. Feb 3, 2009 #3
    oh. wow. thanks.
    now i feel kinda dumb lol i was making it more complicated than i had to, trying trig sub and stuff.
    so [tex]dx=\frac{du}{9}[/tex].
    sweet.
     
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