RE: Problem with Mathematica driving me nuts

• To: mathgroup at smc.vnet.net
• Subject: [mg46826] RE: [mg46791] Problem with Mathematica driving me nuts
• From: "John C. Erb, Ph.D." <John_C_Erb at prodigy.net>
• Date: Tue, 9 Mar 2004 04:31:17 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

```Works fine for me in Mathematica 5.0.1, Windows XP Pro.

Using the Help Browser, it says:
"The AccuracyGoal is automatically set to 1/2 the WorkingPrecision."

Try FindRoot[x^2 == 4*x -4,{x,1},AccuracyGoal->8]

J. Erb

-----Original Message-----
From: benwoodward.com [mailto:bpw67deletethis at hotmail.com]
To: mathgroup at smc.vnet.net
Subject: [mg46826] [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.

```

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