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