Re: [maxima:bugs] #2123 radcan not idempotent

I'm trying this on maxima 5.46.0.
This is peculiar in another way, in that it produces abs(x), which is not
an algebraic function, which radcan should
not return.  Some program has been called internally (simplification) that
converts sqrt(x^2) to abs(x), which
is not a legitimate radcan result.

consider
sqrt(x^2+2*x+1)

radcan(%)   produces x+1    correct.   NOT abs(x+1), which is incorrect,
but consistent with the incorrect abs(x).

RJF


On Sun, Apr 19, 2026 at 9:31 AM David Scherfgen <
[email protected]> wrote:

>
>    - *status*: open --> closed
>    - *Group*: --> None
>    - *Comment*:
>
> This seems to have been fixed at some point.
> ------------------------------
>
> *[bugs:#2123] <https://sourceforge.net/p/maxima/bugs/2123/> radcan not
> idempotent*
>
> *Status:* closed
> *Group:* None
> *Labels:* Lisp Core - Polynomials
> *Created:* Wed Jan 05, 2011 10:01 PM UTC by Stavros Macrakis
> *Last Updated:* Sun Nov 18, 2012 07:53 PM UTC
> *Owner:* nobody
>
> ex: (1-1/x^2)^(3/2)*x$
> radcan(ex) =>
> sqrt(x-1)*sqrt(x+1)*(x^3-x)/(x^2*abs(x))
> Note the factor of x in the numerator and denominator that hasn't been
> factored out.
> radcan(radcan(ex)) =>
> sqrt(x-1)*sqrt(x+1)*(x^2-1)/(x*abs(x))
> The common factor is factored out.
>
> Workaround: A rat or ratsimp before or after the radcan gets rid of the
> problem.
> ------------------------------
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