Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!apple!agate!agate.berkeley.edu!matt From: matt@physics16.berkeley.edu (Matt Austern) Newsgroups: comp.sys.handhelds Subject: Re: Finding roots of Tertiary and above equations? Message-ID: Date: 18 May 91 01:39:53 GMT References: <22117@shlump.nac.dec.com> <283322a6: 2812.1comp.sys.handhelds;1@hpcvbbs.UUCP> <1991May17.230122.21758@zoo.toronto.edu> Sender: root@agate.berkeley.edu (Charlie Root) Reply-To: matt@physics.berkeley.edu Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group) Lines: 21 In-Reply-To: henry@zoo.toronto.edu's message of 17 May 91 23: 01:22 GMT In article <1991May17.230122.21758@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: > Something like HP's numerical solver is often rather more useful in any > case. Even with quadratics it's easy to find cases where the subtraction > operation in the formula nearly destroys the precision of the result, > while numerical techniques don't have that problem. Actually, there are cases where numerical stability is a problem in finding roots of a polynomial---this is especially true if you're trying to find all of the roots. A bigger problem (with HP's solver specifically) is that it doesn't find complex roots. I agree, though, that it's very useful: a page-long analytic solution is rarely enlightening. -- Matthew Austern Just keep yelling until you attract a (415) 644-2618 crowd, then a constituency, a movement, a austern@lbl.bitnet faction, an army! If you don't have any matt@physics.berkeley.edu solutions, become a part of the problem!