Simple questions about Mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg31888] Simple questions about Mathematica
- From: "Stephen Gray" <stevebg at adelphia.net>
- Date: Sun, 9 Dec 2001 06:07:14 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
1. Suppose I solve some equations and get a complicated
expression containing multiple identical elements such as
sqrt(a^2+b^2). To make the expression smaller, clearer, and
easier to deal with, I want to substitute say R=sqrt(a^2+b^2)
everywhere in the main expression and have R available as
a symbol from then on. I see nothing in Help or anywhere
else about how to do this. But it's such a standard thing to
do that there must be an easy answer.
2. I'm not sure how a "batch" file is suppposed to be
prepared and fed to Mathematica. That is, I want to
prepare a bunch of operations and variables in advance
and feed it in, preferably having mathematica give me
line-by-line output as it would if I were typing each line
in one by one.
As a new user I really need answers to these questions.
Thanks in advance for any information.