Bug in NSolve?
- To: mathgroup at smc.vnet.net
- Subject: [mg33788] Bug in NSolve?
- From: rodgerroSPAMNOT.siteconnect.com at library2.airnews.net
- Date: Tue, 16 Apr 2002 03:50:44 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
The Mathematica book says in section 2.9.5:
"NSolve will always give you the complete set of numerical solutions to any
polynomial equation in one variable."
However, Mathematica version 4.1.2 on a Pentium III gives this result:
NSolve[4877361379 x^2 -9754525226 x + 4877163849==0,x,20]
{{ x---> 0.9999797501 }}
On the other hand,
NSolve[4877361379 x^2 -9754525226 x + 4877163849==0,x,10]
gives:
{{ x ---> 0.99998 } , { x---> 0.99998 } }
Machine precision works, but arbitrary precision doesn't?
At least now we get two roots; the correct solution is given by:
N[Solve[4877361379 x^2 -9754525226 x + 4877163849==0,x ] ,10]
which is:
{{ x ---> 0.99998 - 2.89955 x 10^-10 i },{ x---> 0.99998 + 2.89955 x 10^-10i }}
Does anybody know what's going on here?
- Follow-Ups:
- Re: Bug in NSolve?
- From: "Fred Simons" <f.h.simons@tue.nl>
- Re: Bug in NSolve?