On 6/28/2013 9:10 AM, Volker van Nek wrote:
> Hello Robert,
....
>
> E.g. algsys([abs(x-1)/abs(x-5) = 1/3], [x]); yields [] which is
> obviously wrong.
algsys is supposed to solve ALGEBRAIC SYSTEMS.
abs( ) is NOT algebraic.
So algsys renamed abs(x-1) as say w, and abs(x-3) as say z and then
ran algsys([ w/z-1/3],[x])
which has no solutions.
however, squaring both sides converts the problem to an algebraic one.
algsys([(x-1)^2/(x-5)^2 = 1/9], [x]);
gives the solution set
[[x=2],[x=-1]]
If you have a suggestion as to how to explain this in the documentation,
or perhaps how to make the
program clearer in terms of error messages, please offer them. Note
however it is entirely
possible to ask algsys to solve a problem which is algebraic in, say
abs(x-1).
RJF