Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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

    to

    = 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

    Astronuc

    User Avatar
    Staff Emeritus
    Science Advisor

    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

    HallsofIvy

    User Avatar
    Science Advisor

    3/8= 1/4+ 1/8. The 1/4 is the first term and the 1/8 is from the last term.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook