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Why 2L for period?

  1. Mar 9, 2015 #1
    Why do most mathematics literature use 2L for the period of a function? Is it related to heat equation with a rod of length L?
  2. jcsd
  3. Mar 9, 2015 #2


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    Having a rod of length 2L with ends at [itex]\pm L[/itex] instead of a rod of length D with ends at 0 and D makes the mid-point symmetry more obvious.

    Also the period of the sine and cosine functions is [itex]2\pi[/itex] and [itex]\frac{2n\pi x}{2L} = \frac{n\pi x}{L}[/itex] is neater than [itex]\frac{2n\pi x}{D}[/itex].
  4. Mar 9, 2015 #3


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    It may be as simple as noting for a general period, instead of ##2\pi## call it ##2p##. It certainly makes the Fourier coefficient formulas easier to remember. And it's why I like to use ##p## instead of ##L## in such formulas.
    Last edited: Mar 9, 2015
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