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!

I Deriving equation of wave motion

  1. May 28, 2017 #1
    The equation below (2.9) is also a linear differential equation.
    This equation also describes the wave phenomena.
    So, why is this equation not considered as wave equation?
    I have taken it from the optics book by Chapter two Eugene Hecht,5th edition ,Pearson.

    upload_2017-5-28_17-50-0.png upload_2017-5-28_17-50-39.png upload_2017-5-28_17-51-8.png upload_2017-5-28_17-51-45.png
    Last edited: May 28, 2017
  2. jcsd
  3. May 28, 2017 #2
    I must say that this is the worst derivation of the D'Alambert equation I've ever seen. It's simple but seems to describe any differentiable function. It is true that "wave" is a really general concept, in fact there are many different kind of waves and many different equation describing them, but it's not like anything is a wave!
    Anyway, as the text say on page 21, you need at least a second order differential equation to describe a wave since it has in the simplest case an amplitude and a frequency, so two parameters wich requires two conditions.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted