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: Forgot some integration stuff

  1. May 7, 2007 #1
    okay the problem asks to integrate this function from 0-infinity
    i integrated but the answer i get is e^-lambdax from 0 to infinity
    so e^0 is 1
    and you will have 1-e^-lambda(x) where x is infinity
    how does this come out to be -1?
    please explain to me...i think i just forgot a rule
  2. jcsd
  3. May 7, 2007 #2
    Hopefully, you're integrating the function f(x) = -lambda*e^(-lambda*x), otherwise your answer is wrong. The integral of this from 0 to infinity is 1. If you are integrating lambda*e^(-lambda*x), then that is -1.
  4. May 7, 2007 #3
    ok, i think i figured it out. i was completely ignoring the fact that it was a NEGATIVElambda (x). i realized this shortly after posting.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook