RE: Define a function
- To: mathgroup at smc.vnet.net
- Subject: [mg34570] RE: [mg34556] Define a function
- From: "DrBob" <majort at cox-internet.com>
- Date: Wed, 29 May 2002 02:44:10 -0400 (EDT)
- Reply-to: <drbob at bigfoot.com>
- Sender: owner-wri-mathgroup at wolfram.com
Here's a simple solution:
f[x_] := Which[
x < 10, 0,
x < 20, x,
True, x/2
]
Plot[f[x], {x, 0, 30}]
And here's another:
ClearAll[f]
f[x_] /; x < 10 := 0
f[x_] /; x < 20 := x
f[x_] := x/2
Plot[f[x], {x, 0, 30}]
>>I have to define different functions for different ranges of the
variable x.
It's a subtle point perhaps, but in both cases f is ONE function,
defined for all x. (REALLY all x, the way I've done it...) For
instance, evaluate
f["2"]
f[""]
f[{1,2}]
What you mean is that the functional form, expression, or computation
rule is different, for different ranges of the variable.
Bobby Treat
-----Original Message-----
From: Michael Popp [mailto:popp.michael at gmx.at]
To: mathgroup at smc.vnet.net
Subject: [mg34570] [mg34556] Define a function
Hello
I want to define a function in Mathematica. But just f[x_]:=... does
not
work, because I have to define different functions for different ranges
of
the variable x.
For example:
x < 10: f(x) = 0
10 < x < 20: f(x) = x
20 < x: f(x) = x/2
How to do this?
Thanks, greetings
Michael