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Article #249

Re: Graph-TI - Fourier Series

#249
From: Mark Janeba
Date: Thu, 27 Oct 1994 21:44
25 lines
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On 27 Oct 1994, Fleet Rapid Response wrote:

>
> Does anybody know of a program to claculate fourier series?

Why program?  Try this:  For a function on [-1,1], to find a Fourier sine
series (i.e. f is odd):

Put f(x) in y1.  Then the Nth Fourier coefficient is
    fnInt(y1*sin(N*\Pi\*x),x,-1,1)  (Use "N" and not "n" or the '85 balks).

So compute a bunch of coefficients (say the first five) at once:

   seq(fnInt(y1*sin(N*\Pi\*x),x,-1,1),N,1,5,1) -> C

To check your work, graph y1 against

y2=sum seq (C(N)*sin(N*\Pi\*x),N,1,5,1).

If you want cosine series, or some other interval, modify accordingly.

Mark Janeba			(503)370-6123
Dept. of Mathematics		e-mail:  mjaneba@willamette.edu
Willamette University		"Speaking for myself, not the university"
Salem, Oregon 97301-3922 USA	
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Date: Thu, 27 Oct 1994 14:44:56 -0700 (PDT)
From: Mark Janeba <mjaneba@willamette.edu>
Subject: Re: Graph-TI - Fourier Series
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