[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-10 Thread kcrisman
> > > > Interesting. If you have ideas on how to improve it so that you might > do > > so, please start a thread on sage-devel about that. > > I don't. I have expressed my dislike of AskSage as soon as it was > available. It is just that I don't like all these badges and awards and > I do

Re: [sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-10 Thread John Cremona
Sage has two sources of support, the mailing list sage-support and the AskSage site. Users and helpful developers can use whichever they choose, and I don't think that any of us should be telling anyone which one they ought to use, either as an asker of questions or as a helpful answerer. Of cour

[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-10 Thread Simon King
Hi Karl-Dieter, On 2016-11-09, kcrisman wrote: >> > This is a very good question for Ask Sage, would you ask it there? >> >> Why should he? He did ask here. And I, for one, dislike the Ask Sage >> pages to the extent that I wouldn't answer questions there. >> > > Interesting. If you have ide

[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-09 Thread kcrisman
> > This is a very good question for Ask Sage, would you ask it there? > > Why should he? He did ask here. And I, for one, dislike the Ask Sage > pages to the extent that I wouldn't answer questions there. > Interesting. If you have ideas on how to improve it so that you might do so, plea

[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-09 Thread Emmanuel Charpentier
A bit of numerical analysis (see enclosed Jupyter notebook) proves that this polynomial has at least two real roots, and quite probably four), one of them being positive. This triggers the question : does Sage have built-in facilities for uncertainty computation ("calcul d'erreurs" in French, b

[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-09 Thread Simon King
On 2016-11-08, slelievre wrote: > This is a very good question for Ask Sage, would you ask it there? Why should he? He did ask here. And I, for one, dislike the Ask Sage pages to the extent that I wouldn't answer questions there. Cheers, Simon -- You received this message because you are subsc

[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-08 Thread slelievre
Sun 2016-11-06 16:00:30 UTC+1, Francis Banks: > I am solving a polynomial which arises from plotting titration cures > in chemistry. The rule of signs suggests it has one positive root. > Find_root seems to find it. Solve with poly_solve=true does not. > Instead it gives 4 complex roots, which don

[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-06 Thread Dima Pasechnik
On Sunday, November 6, 2016 at 3:00:30 PM UTC, Francis Banks wrote: > > I am solving a polynomial which arises from plotting titration cures in > chemistry. The rule of signs suggests it has one positive root. Find_root > seems to find it. Solve with poly_solve=true does not. Instead it gives 4