Re: simple Problem: D[ ]
- To: mathgroup at smc.vnet.net
- Subject: [mg27325] Re: simple Problem: D[ ]
- From: Albert Retey <albert.retey at visualanalysis.com>
- Date: Wed, 21 Feb 2001 03:16:56 -0500 (EST)
- Organization: Visual Analysis AG
- References: <96t91a$pqt@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Christian Maier wrote: > > I use mathmatica the first time and have a problem with a deriviation: > > in a simple problem: > > f[x]=x^2 > abl=D[f[x],x] > > then Mathematica puts out f[x]' , but not 2 x > > How does it work correctly? > Thank aou in advance! > > Christian Maier f[x]:=x^2 This should do what you want, the colon will cause the left hand side to be evaluated only, when the "pattern" f[x] will be met. For a real "function definition" with arbitrary argument you should use: f[x_]:=x^2 Then even D[f[y],y] should work the way you expect it. Nevertheless, try to first read some introduction to Mathematica, for a beginning the first chapter in the online help -> the mathematica book should do. Albert -- Visual Analysis AG Internet: www.visualanalysis.com Neumarkter Str. 87 Telefon: 089 / 431 981 36 D-81673 Muenchen Telefax: 089 / 431 981 1