Error in FractionalPart?

*To*: mathgroup at smc.vnet.net*Subject*: [mg102411] Error in FractionalPart?*From*: Filippo Miatto <miatto at gmail.com>*Date*: Sat, 8 Aug 2009 04:39:18 -0400 (EDT)

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

**Follow-Ups**:**Re: Error in FractionalPart?***From:*DrMajorBob <btreat1@austin.rr.com>