Reference works are needed!

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg612] Reference works are needed!*From*: Jack Goldberg <Jack.Goldberg at math.lsa.umich.edu>*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. Jack