Re: RE: Solving the Cubic

*To*: mathgroup at smc.vnet.net*Subject*: [mg71916] Re: [mg71883] RE: [mg71859] Solving the Cubic*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sun, 3 Dec 2006 06:26:52 -0500 (EST)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200612021011.FAA27984@smc.vnet.net>*Reply-to*: murray at math.umass.edu

So far as I know, Vieta's method is not intended for numeric approximation. Rather, it is intended to give EXACT solutions in terms of algebraic operations. It's the "cubic formula", analogous to the quadratic formula. (One would not typically use the quadratic formula to give good numeric solutions of quadratics, after all.) Mark Harder wrote: > Dimitris, > Symbolic solutions can be very error- and precision- sensitive (See > Press, et al, "Numerical Recipes.." for a trick that stabilizes quadratic > solutions.) Do you know if Vieta's method designed to avoid numeric > instabilities? > Mark Harder > > > > -----Original Message----- > From: dimitris [mailto:dimmechan at yahoo.com] > Sent: Friday, December 01, 2006 3:22 AM > To: mathgroup at smc.vnet.net > Subject: [mg71883] [mg71859] Solving the Cubic > > The following cell follows the Vieta's method for solving the cubic > equation complete with all the necessary steps and text explanations. > I really appreciate any kind of comments. > > (code omitted ). > > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**RE: Solving the Cubic***From:*"Mark Harder" <harderm@onid.orst.edu>