MathGroup Archive 1995

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Reference works are needed!

  • To: mathgroup at
  • Subject: [mg612] Reference works are needed!
  • From: Jack Goldberg <Jack.Goldberg at>
  • Date: Tue, 28 Mar 1995 10:31:58 -0500 (EST)

Hi group:

   A typical question from a user of Mma is not "what does this command
do?" but rather "how do I accomplish a mathematical task?".  Two examples
of this appeared recently: (1) Simplification of a power of (-1) and (2)
Extracting columns and rows from a matrix subject to certain conditions.
Both questions can be answered by a single Mma command if one knows where
to look.  For (1) the answer is ComplexExpand and for (2) see pg 651 of 
the Book.  The fact that not a single respondent (to my knowledge) pointed
out that the book contains the answer to (2) - highlighted, by the way - 
is evidence on how hard it is to find the correct command(s).  The list  
of commands in the Book is given alphabetically.  But for the user, it is 
a lot like trying to find the spelling of pneumonia by using a dictionary!
(This metaphor might be slightly strained, but anyone who has suffered 
searching for the right function knows exactly what I mean.)
  What we users and teachers need is an Mma "Thesaurus" with an 
accompaning solved problem set.  So, for instance, a user who wants to 
know how to get Mma to write  (-1)^(3/4)  in the form  a + I b  need not 
have to quess ComplexExpand, but rather looks up, say, Numbers, Converting
between representations, etc.  The closest thing we have to this is the 
index in the Book but it is not geared directly to resolving this issue.
  I don't know who would want to devote the time to do this, but I for
one believe there is a strong need for such a reference.  In fact, as I 
write up notes for a class I teach using Mma, I am collecting just such 
a reference for my students, but it will be narrowly focused and quite 
limited.  However, if others are silently doing the same and wish to 
combine resources, we might be able to put together a something useful. 


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