Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Limit involving dirac delta distributions

  1. Feb 26, 2012 #1
    Hey All,

    I am trying to evaluate the limit:
    \lim_{x\to 0^{+}} \frac{\delta''(x)}{\delta''(x)}

    Where [tex] \delta'(x) [/tex] is the first derivative of the dirac distribution and [tex] \delta''(x) [/tex] is the second derivative of the dirac distribution.

    I thought about the fact that this expression will be infinity / infinity and then using L'Hospitals but that doesn't help.

    I guess my question (as someone with an engineering / physics background and not a mathematician) is this limit impossible to evaulate ? and if so is it impossible because taking the limiting value of a dirac distribution doesn't make a whole lot of sense ?

  2. jcsd
  3. Feb 27, 2012 #2
    Sorry I mean to evaulate:
    \lim_{x\to 0^{+}} \frac{\delta'(x)}{\delta''(x)}
  4. Feb 27, 2012 #3
    Try writing the delta function as limit of a Gaussian, for example.
  5. Feb 27, 2012 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Where did this limit come from? I don't believe it even makes sense....
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook