Re: Error in FractionalPart?

*To*: mathgroup at smc.vnet.net*Subject*: [mg102440] Re: [mg102411] Error in FractionalPart?*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Sun, 9 Aug 2009 06:07:07 -0400 (EDT)*Reply-to*: hanlonr at cox.net

I don't see the problem on my system $Version 7.0 for Mac OS X x86 (64-bit) (February 19, 2009) F[x_] := 2 Pi * FractionalPart[x/(2 Pi)] H[x_] := 2 Pi * FractionalPart[-x/(2 Pi)] + 2 Pi FullSimplify[(F[x]^2) (H[x]^2)] 16*Pi^4*(FractionalPart[x/(2*Pi)] - 1)^2* FractionalPart[x/(2*Pi)]^2 Bob Hanlon ---- Filippo Miatto <miatto at gmail.com> wrote: ============= Dear all, I have a little issue while fullsimplifying an apparently simple expression. After defining the functions F[x_] := 2 \[Pi] FractionalPart[x/(2 \[Pi])] H[x_] := 2 \[Pi] FractionalPart[-x/(2 \[Pi])] + 2 \[Pi] I plot the function (F[x]^2)(H[x]^2) between 0 and 4pi and i get something like a double 'gaussian' bell (it's not gaussian, it is just to picture it). Then I enter FullSimplify[(F[x]^2)(H[x]^2)] and I get as a result 16 \[Pi]^4 FractionalPart[x/(2 \[Pi])]^4 which when plotted does not give the same plot, actually it's very different. What am I (or is mathematica) doing wrong? Thank you in advance, Filippo