Re: functions
- To: mathgroup at smc.vnet.net
- Subject: [mg40462] Re: functions
- From: "Steven Shippee" <slshippee at attbi.com>
- Date: Sun, 6 Apr 2003 04:36:02 -0400 (EDT)
- References: <b6m0dv$ehe$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Correction to below and apologies to the group/list: My dyslexia set in, proper syntax for functions would be f[x_] := not as it was mistyped below. David Park has a very nice "elementary" notebook on his website, at URL: http://home.earthlink.net/~djmp/Mathematica.html with his "StepByStepEquations.nb" which is a good place to get started. It helped me out with some things that might come easily to others, but not easily to me. From there it is an easy jump to Mathematica's f[x_] =: Steven Shippee shippee at jcs.mil "Steve Story" <sbstory at unity.ncsu.edu> wrote in message news:b6m0dv$ehe$1 at smc.vnet.net... > This is a general question. > > Functions like DSolve will solve an equation, say, DSolve[{y''[x] == > -2*y[x], y[0] == 0, y'[0] == 1}, y, x] for y or y[x]. However, in my few > months of use of Mathematica, it is very perplexing how it works with y, > y[x], interpolating functions, substitution. It is not clear how to use > the results of things. When to substitute with the /. operator, when > not, when to use Evaluate, when not, how to use the output as an > ordinary function... I have had limited success understanding these > issues with the mathematica book. Does anyone know a source of > information explaining these topics so that when I get an output from > for instance an NDSolve function there's no confusion about how to use > it in various circumstances like Plotting and such? It's perplexing. > > thanks, > Steve Story > >