Re: Extract Coefficients of Fourier Series
- To: mathgroup at smc.vnet.net
- Subject: [mg58823] Re: Extract Coefficients of Fourier Series
- From: mike_in_england2000 at yahoo.co.uk
- Date: Wed, 20 Jul 2005 00:29:21 -0400 (EDT)
- References: <dbie2e$brj$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi
In order to illustrate how I went about this I created some random data
and TrigFit returned something like this.
0.576739 + 0.128598 Cos[x] + 0.0328485
Cos[2 x] - 0.018517 Cos[3 x] + 0.0484222 Cos[4 x]
So I call this functiuon fit[x] -
fit[x_]:=0.576739 + 0.128598 Cos[x] + 0.0328485
Cos[2 x] - 0.018517 Cos[3 x] + 0.0484222 Cos[4 x]
The constant term I get by doing
const = fit[x][[1]];
the rest of the terms I get using a loop:
Do[
coeff = fit[x][[n]][[1]];
Print[coeff];
, {n, 2, Length[fit[x]]}
]
which should print out the coefficients. I'll leave it to you to
modify the loop so instead of printing them you square and add them up.
hope this helps
Mike