Re: Problem with Mathematica driving me nuts
- To: mathgroup at smc.vnet.net
- Subject: [mg46827] Re: Problem with Mathematica driving me nuts
- From: Janusz Kawczak <jkawczak at math.uncc.edu>
- Date: Tue, 9 Mar 2004 04:31:19 -0500 (EST)
- References: <c2he1m$ahd$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Yes, the Newton's method is used. Why don't you try something
like Solve[] or
In[1]:=<< NumericalMath`InterpolateRoot`
In[2]:=InterpolateRoot[4 - 4 x + x^2 == 0, {x, 0, 1}, ShowProgress ->
False,
WorkingPrecision -> 70, AccuracyGoal -> 65, MaxIterations -> 100]
Out[2]:={x -> 2.000000000000000000000000}
You can change ShowProgress -> False to True to see how it's calculated.
Janusz.
"benwoodward.com" wrote:
> 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.