> On Mar 20, 3:40 am, Bruce Bartlett <brucehbartl...@googlemail.com> > wrote: > > > When I type in > > > plot(x^(1/3), -1, 1) > > > Sage balks at me. Apparantly it doesn't understand that the cube root of a > > negative number is well defined. Is this a bug? I found no easy way to get > > around it. > > In the documentation for plot (which you can see by doing plot?), it > says > > To plot the negative real cube root, use something like the > following:: > > sage: plot(lambda x : RR(x).nth_root(3), (x,-1, 1))
Just for context, this was discussed ad nauseam a long time ago, and essentially the argument is that a) there are way too many places where (-1)^(1/3) should be in fact the primitive complex root of negative unity, even when it is not explicitly asked for via using the complex number framework in Sage and b) it's not clear that there is any way to make the plotting code "know" that one is plotting something like this, because there are too many similar things to catch. I also believe Maple does not plot the negative values. I wish there were an easier way around this, but none has occurred to any of us so far. Believe me, I'd be the first to implement something which allowed a) to work but which still caught cases of b). - kcrisman --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
