On Tue, Dec 16, 2014 at 1:20 AM, rjf <fate...@gmail.com> wrote:
>
> Well, you could assert that there is no discussion, but you are apparently
> wrong.
> sqrt has 2 values except at zero. (in the complex plane, or on the real
> line).
>
> for example, sqrt(9) is the set {-3,3} . That is how it is extended.
> and sqrt(1) is {-1,1}.
>
> Is it true that 1 is equal to {-1,1} ?
>
> Now you could insist that sqrt() means only one of the roots. Etc for other
> roots and for
> other domains. But you would have to fill in what Etc means.
>
>
> What do you suppose is going on at WRI, and with Maxima, each refusing to do
> this?
sqrt(x) (or Sqrt[x] in Mathematica) denotes the principal square root
in every computer algebra system I can think of, even in Maxima:
(%i1) sqrt(1);
(%o1) 1
Why should solve() work with a different definition of sqrt() than the
definition the system uses for evaluation?
I propose naming this context-dependently non-principal sqrt function
of yours the "strawman square root".
Fredrik
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