1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Integral of an Exponential function

  1. Jun 25, 2010 #1
    Hello every one,

    I was doing my research and then I simply struck at a point.
    The point is that i do not know how to solve the following Integral. I am not at all bad at doing math but some times I got blanked.

    so, here is the Integral,


    Integral (infinity,u) exponent^(-u) du

    result with derivation or with some reference will be highly appreciated.

  2. jcsd
  3. Jun 25, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper

    Err, that doesn't really make sense. Do you mean,
    [tex]\int_{u}^\infty e^{-v} \, dv[/tex]
    by any chance (with the boundaries in the correct order and where the integration variable is a dummy not occurring in the integration boundary).
  4. Jun 25, 2010 #3
    ok, if it is the case then what will be the answer ?
  5. Jun 25, 2010 #4
    In a research paper, I found a solution to a similar problem.


    please look at it
  6. Jun 25, 2010 #5


    Staff: Mentor

    This is not that similar. Your problem, assuming that it is as CompuChip suggested, is
    [tex]\int_u^{\infty} e^{-v}dv[/tex]

    First, find an antiderivative using substitution.
    Second, evaluate the improper integral using limits.

    This is not a very complicated integral.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook