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: Infinite integral

  1. Sep 23, 2008 #1
    Working with Fourier integrals, I need to find the integral

    [tex]\int cos (wv) dv[/tex] between -[tex]\infty[/tex] and [tex]\infty[/tex]. Is it possible to find this integral?

    What I get is sin(wv)/(pi*w) with the infinite limits for v.
  2. jcsd
  3. Sep 23, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    Where did the pi come from? In the sense of a ordinary integral it makes no sense, it's divergent. In the sense of a fourier integral it can make some sense, if you are also integrating over w. But I think you need to give us the complete context.
  4. Sep 24, 2008 #3


    User Avatar
    Science Advisor

    If you are working with Fourier series, why are you integrating from negative infinity to infinity? The integral should be over one period.

    If you are working with the Fourier transform, why are you integrating cosine? Write everything in terms of exponentials: cos(wv)= (ewv+ e-wv)/2.

    As Dick said, please give us the entire problem.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook