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Homework Help: Frouier series problem

  1. Mar 24, 2008 #1
    [SOLVED] Frouier series problem

    Lately I took Frouier series...
    1. The problem statement, all variables and given/known data

    Find the Fourier series of the function below which is assumed to have the period 2 [tex]\pi[/tex], and find the first three partial sums.

    http://www.imagehosting.com/out.php/i1650739_untitled.JPG

    2. Relevant equations


    3. The attempt at a solution

    I used office 2007 to write my solution....and here they are hosted as a picture..
    http://www.imagehosting.com/out.php/i1650792_untitled1.JPG

    I see my answer not correct, I hope someone helps me..Thanks
     
    Last edited: Mar 24, 2008
  2. jcsd
  3. Mar 24, 2008 #2

    G01

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    You are correct to integrate from -pi to pi in the integral, but your function is non-zero over that entire interval, so I do not know why you have the function value as 0 in [tex][-\pi , -\pi/2][/tex] and [tex][\pi/2 , \pi][/tex].

    Also I believe your constant in front of your integral for a_n is incorrect. The constant in front of that integral should be:

    [tex]\frac{2}{Period}=\frac{2}{2\pi}=\frac{1}{\pi}[/tex]
     
    Last edited: Mar 24, 2008
  4. Mar 25, 2008 #3
    sorry, there is a wrong in the picture of the function...the correction is
    -2Pi becomes -Pi; -Pi becomes -Pi/2; Pi becomes P/2; and 2Pi becomes Pi.

    so 'GO' the 0's in the integrals you specified becomes right with me..and you are correct about a_n, it should be 1/Pi and the same in the denominator of the cosine in that line..
     
  5. Mar 25, 2008 #4

    G01

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    OK your integration makes sense then.

    BTW. I usually imagine my PF name being pronounces "G Zero One." :wink:

    So, was the constant your problem or do are you still having trouble?
     
  6. Mar 26, 2008 #5
    yes it was the constant..it's now solved..thanks
     
  7. Mar 28, 2008 #6

    G01

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    Glad to be of help.:smile:
     
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