Re: Differentiating Piecewise Functions
- To: mathgroup at smc.vnet.net
- Subject: [mg14825] Re: Differentiating Piecewise Functions
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Wed, 18 Nov 1998 01:29:30 -0500
- Organization: University of Western Australia
- References: <72e2q0$oi3@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Des Penny wrote:
> I've got a problem understanding how Mathematica finds the derivative of
> a piecewise function.
>
> Consider the following:
> In[1]:=
> Clear[f]
> f[x_ /; (x<0)]:=x;
> f[x_ /; (x>=0 && x<3)]:=Sin[x];
> f[x_ /; (x>=3)]:=x-4;
Not an answer to your question -- but another approach to your problem
is to use FunctionInterpolation:
g = FunctionInterpolation[f[x], {x, -5, 10},
InterpolationPoints -> 30, MaxRecursion -> 8];
Plot[Evaluate[{g[x], g'[x]}], {x, -5, 10},
PlotStyle -> {Hue[0], Hue[1/3]}];
Cheers,
Paul
____________________________________________________________________
Paul Abbott Phone: +61-8-9380-2734
Department of Physics Fax: +61-8-9380-1014
The University of Western Australia Nedlands WA 6907
mailto:paul at physics.uwa.edu.au AUSTRALIA
http://www.physics.uwa.edu.au/~paul
God IS a weakly left-handed dice player
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