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

Using L'hopital's rule in exponential function

  1. Feb 29, 2012 #1
    Is that any way to find a finite value which is not equal to zero using L'hopital's rule in

    limit(z=-ia)
    exp[-A/(z+ia)]/(z+ia)^2

    i kept getting 0/0 after differentiation

    Thank you
     
  2. jcsd
  3. Feb 29, 2012 #2

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    So your problem is
    [tex]\lim_{z\to -ia}\frac{e^{-A/(z+ ia)}}{(z+ia)^2}[/tex]
    ?
    Instead, write the exponential as a Laurent series around -ia. It should be clear that you will have a "1" as the constant term and so the limit will not exist. This function has a pole of order 2 at z= -ia.
     
    Last edited: Mar 1, 2012
  4. Mar 1, 2012 #3
    Thank you very much HallsofIvy....i got what u meant..
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Using L'hopital's rule in exponential function
  1. L'Hopital's Rule (Replies: 7)

  2. L'Hopital's rule (Replies: 19)

Loading...