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Quantum Mechanics - Leonard Susskind on Integration by Parts

  1. Oct 2, 2011 #1
    I'm watching the video series on Quantum Mechanics taught by Leonard Susskind, (from Stanford).

    On Lecture #3, Dr. Susskind says that integration by parts is:

    ∫FG' = -∫GF'

    However from what I know integral by parts to be, there i missing a +FG on the righthand side, or something... since I don't recognize that as the same as
    ∫FdG = FG - ∫GdF

    The specific function that was being dealt with was the wavefunction ψ, (where F = G = ψ) so maybe that could have to do with it... I don't think ψ^2 = 0 though.

  2. jcsd
  3. Oct 2, 2011 #2


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    The "FG" part is evaluated at the boundary. I assume there are boundary conditions that make that term vanish.
  4. Oct 2, 2011 #3
    He mentioned something about boundary conditions, could you explain to me what you mean? What boundary conditions could make the term vanish?
  5. Oct 2, 2011 #4
    If F or G is some wavefunction ψ then the boundary condition says that ψ goes to 0 at x = + or - infinity.
  6. Oct 2, 2011 #5
    Right ok thanks, I lost my mind there a little bit!
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