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Homework Help: Integration of A exp( (− 3 R^2)/(2Na^2))

  1. Sep 22, 2014 #1
    Could someone please integrate the expression (with intention of finding the normalisation constant / value of A).

    Thanks a lot!

    Attached Files:

  2. jcsd
  3. Sep 22, 2014 #2


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    No one here will do the problem for you. You should make an attempt to solve the problem, then ask questions from there.
  4. Sep 22, 2014 #3

    Ray Vickson

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    Your post violates PF standards and requirements. Please read the 'pinned' post by Vela, entitled 'Guidelines for students and helpers'.

    In particular: (1) do not post thumbnails---type out the problem. (2) You MUST do and show some work on the problem first, before posting; this is not a homework service
  5. Sep 22, 2014 #4
    Excuse me; I was being hurried (thanks for the heads up, regardless). The thumbnail was posted for context.
    (should I reformat and post a new thread?)

    The real cheese here is integrating
    A exp( (− 3 R^2)/(2Na^2))

    I know that to find A / the normalisation constant, I should make the integrated expression equal to 1 (and then cube A for to get actual A for R).

    It's integrating ^ that's my primary issue, any help would be great.

    Thanks you!
  6. Sep 22, 2014 #5
    Would the first step be to arrange it as A(e^-3R^2)(e0.5Na^2) ?
  7. Sep 22, 2014 #6


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    You need to tell us the complete problem first. You haven't said what variable you're integrating with respect to. You haven't specified the limits of integration, or perhaps it's an indefinite integral you're looking for. You also need to review basic properties of exponentials. In particular, you should know that ##e^a e^b = e^{a+b}##. Your rearrangement isn't equal to the original.

    Once you get the details down, what's stopping you from evaluating it? Have you even tried to do it on your own yet?
  8. Sep 22, 2014 #7
    The expression is equal to P(N,R).
    Limits are infinity to - infinity.
    I need to find A in terms of N and a.
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