On Sat, Jan 24, 2009 at 11:08 AM, andre maute <andre.maute at gmx.de> wrote:
> (%i3) integrate(x/(1-x),x,-1,1)
> Is zeroa positive, negative, or zero?
> what does zeroa mean here?
zeroa is an internal symbol for a positive infinitesimal (sort of).
The fact that it is being displayed to the user is a bug. Anyway,
asksign should know that zeroa>0 and zerob<0.
> (%i3) integrate(1/x,x,-1,1)
> Is x-1 positive, negative, or zero?
> ----------------------------------------------------------
>
> isn't x-1 < 1-1 = 0?
> how does this pnz question help here?
Yes, definite integration should be cleverer here. Not exactly a bug,
but not the best behavior.
-s