Re: Problem with Mathematica driving me nuts
- To: mathgroup at smc.vnet.net
- Subject: [mg46825] Re: [mg46791] Problem with Mathematica driving me nuts
- From: Tomas Garza <tgarza01 at prodigy.net.mx>
- Date: Tue, 9 Mar 2004 04:31:16 -0500 (EST)
- References: <200403080910.EAA10442@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Unable to reproduce your results. I'm using Version 5.0.1 under Windows XP. Of course, you'll never get x->2, since Mathematica uses a numerical method (see Implementation Notes in the Help Browser: Polynomial root finding is done based on the Jenkins-Traub algorithm). My approximation is better than yours, anyway: In[1]:= FindRoot[x^2 == 4*x - 4, {x, 1}] Out[1]= {x -> 1.9999999701976776} In[2]:= FindRoot[x^2 - 4*x + 4, {x, 3}] Out[2]= {x -> 2.0000000298023224} In this case, however, you may try Solve: In[3]:= Solve[x^2 == 4*x - 4, x] Out[3]= {{x -> 2}, {x -> 2}} Tomas Garza Mexico City ----- Original Message ----- From: "benwoodward.com" <bpw67deletethis at hotmail.com> To: mathgroup at smc.vnet.net Subject: [mg46825] [mg46791] Problem with Mathematica driving me nuts > FindRoot[x^2 == 4x - 4, {x, 1}] > > Out[4]= > {x -> 1.99902} > > In[15]:= > FindRoot[x^2 - 4*x + 4, {x, 3}] > > Out[15]= > {x -> 2.00098} > > When the root is clearly two. > Is Mathematica using Newton's Method like a Ti-92? > Even if so, why wont it give a more accurate answer? > I've tried N[%,30] but it doesn't do anything. > I'm new to Mathematica coming over from a Ti-92, so everything is > frustrating right now. > Thanks. > >
- References:
- Problem with Mathematica driving me nuts
- From: bpw67deletethis@hotmail.com (benwoodward.com)
- Problem with Mathematica driving me nuts