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Re: restricting range?

• To: mathgroup at smc.vnet.net
• Subject: [mg57433] Re: [mg57429] restricting range?
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Sat, 28 May 2005 05:38:56 -0400 (EDT)
• Reply-to: hanlonr at cox.net
• Sender: owner-wri-mathgroup at wolfram.com

f[t_]:=Which[t<1/4, a*t, True, 0];

f[t]

Which[t < 1/4, a*t, True, 0]

Simplify[f[t],t<1/4]

a t


Bob Hanlon

> 
> From: Ken Turkowski <turk at worldserver.com>
To: mathgroup at smc.vnet.net
> Date: 2005/05/27 Fri AM 04:57:59 EDT
> Subject: [mg57433] [mg57429] restricting range?
> 
> I have a function that has multiple branches (using Which), but I would 
> like to restrict its evaluation to one branch for purposes of feeding 
> into Solve.
> 
> I tried
>    f[t] /; t<1/4
> and
>    (t < 1/4) && f[t]
> but neither works. I know I've seen something like this for square roots 
> in the Mathematica book,
>    Sqrt[x^2] restricted to (Im[x] == 0) && (x >= 0)
> but I can't find it. Can you help me?
> 
>