1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fourier sine series quick question

  1. Mar 23, 2015 #1
    I'm having trouble understanding a part in my book.

    second to last paragraph where it says 4.2 must be the Fourier sine series for x^2, how did the author arrive at that?


    http://i.imgur.com/gLLUYXw.jpg
     
  2. jcsd
  3. Mar 23, 2015 #2

    joshmccraney

    User Avatar
    Gold Member

    The author was familiar enough with fourier series to recognize the expression arrived at is the sine expansion of ##x^2##. To verify, simply find the fourier sine series of ##x^2##.

    There is no reason why most people would recognize this, especially if you're just learning it, so I wouldn't worry about it too much.
     
  4. Mar 23, 2015 #3

    LCKurtz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Something is wrong there. That is not the half range sine for series for ##x^2##. The odd periodic extension of ##x^2## is discontinuous so the coefficients could converge no faster than order of ##\frac 1 n##. It is in fact the correct sine series for ##f(x) = x(\pi -x)## as is stated.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Fourier sine series quick question
  1. Fourier Sine Series (Replies: 3)

  2. Fourier Sine Series (Replies: 2)

  3. Fourier sine series (Replies: 30)

Loading...