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Homework Help: Confusing integral!

  1. Feb 4, 2010 #1
    1. The problem statement, all variables and given/known data
    0e-t dt
    (integral from 0 -> ∞)

    2. Relevant equations



    3. The attempt at a solution
    so far, i have...
    0e-t dt
    ={-e-t}0
    = -e-∞ - -e0
    = 0 + 1 = 1

    but looking at a graph, it approaches zero. What am I doing wrong??
     
  2. jcsd
  3. Feb 4, 2010 #2

    tiny-tim

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    Welcome to PF!

    Hi _Steve_! Welcome to PF! :smile:
    Nothing! :smile:

    The graph starts at 1, and ends approaching zero.

    The integral is the area under it, and it's so thin at the "infinity" end that the total area is 1. :wink:
     
  4. Feb 4, 2010 #3
    Oh, hahaha, now I feel like an idiot :tongue:
    Thanks!
     
  5. Feb 4, 2010 #4

    tiny-tim

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    he he! :biggrin:

    my work here is done! o:)
     
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