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Re: Error in FractionalPart?

• To: mathgroup at smc.vnet.net
• Subject: [mg102461] Re: [mg102411] Error in FractionalPart?
• From: DrMajorBob <btreat1 at austin.rr.com>
• Date: Mon, 10 Aug 2009 04:14:34 -0400 (EDT)
• References: <200908080839.EAA01326@smc.vnet.net>
• Reply-to: drmajorbob at bigfoot.com

I get a different simplification:

FullSimplify[f[x]^2 h[x]^2]

16 \[Pi]^4 (-1 + FractionalPart[x/(2 \[Pi])])^2 FractionalPart[x/(
   2 \[Pi])]^2

and the plots look the same.

Bobby

On Sat, 08 Aug 2009 03:39:18 -0500, 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
>



-- 
DrMajorBob at bigfoot.com

• References:
  • Error in FractionalPart?
    • From: Filippo Miatto <miatto@gmail.com>