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Homework Help: Oscillations & Waves Function

  1. May 26, 2012 #1
    1. The problem statement, all variables and given/known data

    The following is a question from an old assignment on coupled oscillators and waves:

    http://img214.imageshack.us/img214/601/question2.jpg [Broken]

    3. The attempt at a solution

    So, I'm a confused about the meaning of the subscripts fpq and fqp. What do they mean?

    Do fp and fq refer to partial derivatives of the function? If so what do fpq and fqp mean?

    I've consulted the textbook physics of vibrations and waves, but I couldn't see what these subscripts stand for. Any help or suggestion would be greatly appreciated.
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. May 26, 2012 #2
    The symbol [itex]f_p[/itex] represents the partial derivative of [itex]f[/itex] with respect to [itex]p[/itex] (and similarly for [itex]q[/itex]) while the symbol [itex]f_{pq}[/itex] may be better understood when rewritten as [itex](f_p)_q[/itex]. In words, differentiate [itex]f[/itex] with respect to [itex]p[/itex] and then differentiate the resulting derivative with respect to [itex]q[/itex].
  4. May 27, 2012 #3
    Thank you so much for the clarification. I see, the notation they've used wasn't clear.
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