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Homework Help: Speed of wave.

  1. Feb 16, 2008 #1
    1. The problem statement, all variables and given/known data
    What's the speed and direction of the following wave(A,B and C are constants)

    3. The attempt at a solution

    from (x-Ct)

    v=C in the +x direction
  2. jcsd
  3. Feb 16, 2008 #2
    Are you missing the imaginary constant in your exponential? If so, then you are correct. If not, you have a diverging or decaying exponential rather than a plane wave.
  4. Feb 16, 2008 #3
    No,it's original question.There's no imaginary constant.
    So my solution is true.Thanks for checking.
  5. Feb 16, 2008 #4
    No, there has to be an imaginary constant. You need to have something of the form


    Regular exponentials don't satisfy the wave equation. The wave equation says that two derivatives in time equal two derivatives in space divided by the velocity squared.
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