Re: How to define a polyfunction?

• To: mathgroup at smc.vnet.net
• Subject: [mg27403] Re: How to define a polyfunction?
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Sun, 25 Feb 2001 00:53:26 -0500 (EST)
• Organization: Universitaet Leipzig
• References: <974vp8\$6jh@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

in the last case it's easy as well:

golf[t_] := t^2 - t

keycond[tau_?NumericQ] := Module[{t}, TrueQ[D[golf[t], t] > 0 /. t ->
tau]]

Key[t_?NumericQ] /; keycond[t] := t^4 + t*3

Key[t_?NumericQ] := (t^2.5 - t)

Regards
Jens

liwen liwen wrote:
>
> Dear friend,
>          How are you!Now I encounter a problem that I
> can not solve for a long time .
> It can be express simplely as how to define a
> polyfunction,for example,a simple polyfunction may be
> defined as that:
>
> Key[t_]:=If[(t>0),1,0];
>
> It is easy to define.However,it will be more difficult
> when the condition turns more complicate.For instance:
> golf=t^2-t;
> Key[t_]:=If[(D[golf[t],t]>0),(t^4+t*3),(t^2.5-t)];
>
> Best regards,
>
> Liwen
> E-mail:  gzgear at yahoo.com
>
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Auctions - Buy the things you want at great prices! http://auctions.yahoo.com/

```

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