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Re: How to express this function.

• To: mathgroup at smc.vnet.net
• Subject: [mg84237] Re: How to express this function.
• From: "David W.Cantrell" <DWCantrell at sigmaxi.net>
• Date: Fri, 14 Dec 2007 23:16:53 -0500 (EST)
• References: <fjunch$27q$1@smc.vnet.net>

"huxiaopengstat at gmail.com" <huxiaopengstat at gmail.com> wrote:
> f is  a period continual function with period  1.
> f equals x when 0<x1/2,equals -x when -1/2<x<1.

I must suppose that you meant -x when -1/2<x<0.

> How to express this function?

There are many ways to do that in Mathematica. One way, using the Floor
function, is

f[x_]:= (-1)^Floor[2 x] ((2 x - Floor[2 x])/2 - 1/4) + 1/4

David

• Follow-Ups:
  • Re: Re: How to express this function.
    • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>