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Homework Help: Normalization of time independent wave function

  1. Jun 20, 2009 #1
    1. The problem statement, all variables and given/known data
    normalize the wave function [tex]\Psi(x)= Acos(\Pi*x/a)[/tex] to show that A=[tex]\sqrt{2/a}[/tex]

    3. The attempt at a solution
    i dont know how to get that answer as all i can tell, normalizing gives:
    [tex]-A^{2}pi^{2}2x/a^{2} * sin (pix/a)[/tex]

    However this does not give the right answer for A
    Any help pointing out what ive missed would be great.
  2. jcsd
  3. Jun 20, 2009 #2
    Hi Skullmonkee,

    Let me ask you a question first:

    What expression "defines" the normalization of a wavefunction?
  4. Jun 21, 2009 #3
    Do you mean this?

    [tex]\int\Psi^{*}\Psi dx=1[/tex]

    [tex]\int Acos(\pi x/a)*Acos(\pi x/a)dx[/tex]

    = [tex]\int A^{2}cos^{2}(\pi x/a)[/tex]

    But im not sure where to go from here?
  5. Jun 25, 2009 #4


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    What are the limits of integration? I.e., over what range of x is the wavefunction defined?
  6. Jun 26, 2009 #5


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    Gold Member

    You need to plug in the limits of integration. You can't normalize a wave function using indefinite integration.
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