Dear Guiseppe
Of course you can obtain a Fourier Series representation for
a periodic, piecewise defined function. I have done it many times.
For example, say u(t) = -3 for -3 < t < 0 and = 2t for 0 < t < 5
and that u(t+8)=u(t) for all t.
Use the CHI function to define u(t) over the periodic interval (-3, 5)
namely u(t):=CHI(-3,t,0)(-3)+CHI(0,t,5)2t
then issue the Fourier command i.e. Fourier(u(t),t,-3,5,5) .
Then simplify or approximate and then plot to obtain the desired
representation.
I also have a periodic_plot command to plot a selected number of
cycles of any piecewise defined periodic function. It is quite nice to
see how the Fourier series representation compares with the original
wave form.
I hope this helps,
Regards,
Boz Kempski.
-----Original Message-----
From: Giuseppe Ornaghi <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: 11 February 2000 19:38
Subject: help on Fourier
>Can I expand a piecewise function with the function Fourier(y,t,t1,t2,n)
>with DfW 4.11 ?
>Best regards
>Giuseppe Ornaghi
>[log in to unmask]
>
>
>
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