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Calc3-line integral

  1. Feb 28, 2005 #1
    1) Integral of bound C of function x*e^y ds; C is the line segment from (-1,2) to (1,1).
    How do i get the bound and the x and y in parameter form?
    Show me plz!!! I need to learn!!
    2)A wire w/ constante density has the sahpe of the helix x=a*cos(t), y=a*sin(t), z=bt, 0<=t<=3 pi. Find its mass a center of mass
    For this one, is the function = k, for which k is any constant??? and then do the integral from 0 to 3 pi??

    **mass = integral from 0 to 3 pi, of k*sqrt[ -a^2*sin^2(t) +a^2*cos^2(t)+b^2] dt ??
    Thanks so much
  2. jcsd
  3. Mar 1, 2005 #2


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    For the second,you may want to check again the differentiation.The integral is very simple...

  4. Mar 1, 2005 #3


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    There are many ways of getting an upper bound of xe^y on the line segment.
    Since on this segment [itex]|x|\leq 1[/itex] and [itex]e^y \leq e^2[/itex] we have [itex]|xe^y|\leq e^2[/itex].

    Not sure if this was what you were looking for.
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