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Homework Help: Quick question on integral distribution

  1. Sep 15, 2007 #1
    So one example in my book goes from this step:

    Integral of[1/4 + cos2x/2 + 1/4((1+cos4x)/2)] dx


    = 3/8Integral dx + 1/4integral 2cos2xdx + 1/32integral 4cos4x dx

    I am very confused as to why, in the process od destribution, the integral became 3/8intdx as opposed to just int 1/4dx and so forth... Where did that 3/8 come form???

    Thank you!
  2. jcsd
  3. Sep 15, 2007 #2


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    Integral of[1/4 + cos2x/2 + 1/4((1+cos4x)/2)] dx

    Expand the third term and regroup terms of dx, cos 2x dx, cos 4x dx
  4. Sep 15, 2007 #3


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    3/8= 1/4+ 1/8. The 1/4 is the first term and the 1/8 is from the last term.
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