There is no algebraic difference between +I and -I, so one needs
make no difference between them. ONLY WHEN one fixes a topological
representation of $C$ as a plane (for example) and gives it an
orientation, etc... one gets a "real" difference, but from the
purely algebraic (and that is what a CAS does) point of view,
one cannot (is not able to) make any difference between "the" two
roots of x^2+1=0 over $R$. The fact could be stated as:
let us begin to work. Now, I need to work with the solution of
x^2+1. OK. If there is one, then there are two (characteristic
0, IMPORTANT). OK. Let us call one I. Let us call the other J.
Mmmmmh! It happens that J=-I. That's good! Then, instead of using
J, we shall use -I.
Hope this helps to clarify things.
Pedro.
--
Pedro Fortuny Ayuso -------> www.geocities.com/pedro_fortuny
School of Mathematical Sciences, Queen Mary and Westfield College
Mile End Road, London E1 4NS, UK -----> www.maths.qmw.ac.uk
On Wed, 26 Sep 2001 maxima-request@www.ma.utexas.edu wrote: