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Homework Help: Better integration strategy?

  1. Apr 4, 2010 #1
    I'm doing a HW problem that involved trying to find Fourier series. I know how to do it, but I'm really bothered by the fact that I have to do so much trigonometric integration by parts. my question is, is there any better way to solve the problem:

    <int,indef.,dt>{ sin(a*t)*cos(b*t) } or is the only way to chug along with the two messy layers of integration by parts?

    also, it seems like i'm missing something: how do you write pretty-print equations in posts?

    edit: i should add, that the problem is asking for a fourier series for a half-wave rectified sine, but that isn't vital to the question
  2. jcsd
  3. Apr 4, 2010 #2


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    Homework Helper
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    Why are you concerned with the indefinite integral? Usually one integrates over a half-period interval in order to take advantage of the orthogonality of sine and cosine.

    See my signature.
  4. Apr 4, 2010 #3
    thanks for the reply. I'm only concerned because it seems like I'm doing it the hard way - after 1.5 pages of math, I'm starting to feel like I'm mowing the lawn with a pair of nail clippers (or mopping a gym floor with a toothbrush, take your pick of metaphor). I just wanted to make sure that by parts is the only reasonable way of doing it and I'm not missing any good shortcut.
  5. Apr 5, 2010 #4
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