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Homework Help: Exponential Integral

  1. Nov 5, 2009 #1
    1. The problem statement, all variables and given/known data
    i have to integrate e^(-y) / y
    and i found out that you have to use this exponential integral and someone else said it doesnt have an integral. either way im thoroughly confused

    3. The attempt at a solution
    i have no clue what so ever. The original question had it in dy/dx=y*e^(x+y) but that above question is all i need help with.
  2. jcsd
  3. Nov 5, 2009 #2


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    Hi brandy! :smile:

    (try using the X2 tag just above the Reply box :wink:)

    If you keep integrating by parts, you get a power series times e-y
  4. Nov 5, 2009 #3
    [tex]\int\frac{e^{-y}}{y}dy = \int-\frac{e^{-y}}{-y}dy[/tex]

    Let x = -y, then dx = -dy.

    [tex]\int-\frac{e^{-y}}{-y}dy = \int\frac{e^x}{x}dx[/tex]

    You can rewrite it as the same integral you had in the other thread, which still doesn't have an elementary integral.
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