[Maxima] unsimplifed result from expand
Dieter Kaiser
drdieterkaiser at web.de
Sat Mar 26 10:07:35 CDT 2011
Am Samstag, den 26.03.2011, 09:32 -0500 schrieb Barton Willis:
> I thought that expand returned a simplified expression; maybe it does not:
>
> (%i241) (1-sqrt(5))^3-4*(1-sqrt(5))^2+8;
> (%o241) (1-sqrt(5))^3-4*(1-sqrt(5))^2+8
>
> (%i242) expand(%);
> (%o242) 5^(3/2)-5^(3/2)
>
> (%i243) expand(%,0,0);
> (%o243) 0
>
> Ratexpand crunches this to zero without the additional simplification:
>
> (%i244) ratexpand((1-sqrt(5))^3-4*(1-sqrt(5))^2+8);
> (%o244) 0
>
> --Barton
This problem might be related to a further bug I have observed some time
ago:
(%i4) sqrt(2)+sqrt(2)+sqrt(2);
(%o4) 2^(3/2)+sqrt(2)
(%i6) ratsimp(%);
(%o6) 3*sqrt(2)
The problem is in simplus and related functions. We have code in
simptimes to simplify powers of integers. simplus has to be extended
accordingly. I have already tested some algorithm, which works for the
case above, but it is not general enough.
Dieter Kaiser
More information about the Maxima
mailing list