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Homework Help: Zwiebach page 208

  1. Oct 24, 2007 #1
    1. The problem statement, all variables and given/known data
    should there be a d/dt in equation 12.17? there is not in my book?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 25, 2007 #2
    Yes, there should be a dot over the \xi on the l.h.s. and in my copy there is. Perhaps your copy is older than mine. This would shed light on a earlier thread.
  4. Oct 25, 2007 #3
    Sorry, I see the dot now. It just kind of blends in with the top of the \xi. I am pretty sure I have the most recent version.
  5. Oct 25, 2007 #4


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    We had a discussion a bit earlier about something concerning n dot P being zero everywhere along the string or something to that effect. And it was clear that you had an earlier version than what Jimmy has (and you had the same version I own). Did you get your hands on a more recent copy now?
  6. Oct 25, 2007 #5
    My recollection of that thread is different.

    I asked Ehrenfest for information on the printing number from the copyright page, but he said there was none. Mine doesn't have any either, but I had advance knowledge that the book would be published and bought it as soon as it was available. Bottom line, I am not sure whether his copy is earlier or later than mine. The text in his copy is 'better' than mine in the place that was the topic of that thread, and that would indicate a later printing, but you can't be 100% sure. I don't think either version is completely satisfactory.

    When Ehrnefest said that there was no derivative in his copy, it raised my hopes that his copy was earlier than mine. It is too unlikely that the book would deteriorate in that way. Unfortunately, from this point of view, the derivative is there after all. Without printing number information in the book, I see no clear evidence either way.
  7. Oct 25, 2007 #6
    Here is a quote from my copyright page:


    First Published 2004
    Reprinted 2004, 2005
    Reprinted 2005 (twice), once with corrections.


    I am not sure whether I put that in the other post. I bought my book from amazon in August.
  8. Oct 25, 2007 #7
    Thanks. What you have is definitely later than mine which simply says:
    First Published 2004
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