Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2008

[Date Index] [Thread Index] [Author Index]

Search the Archive

Two FindRoot questions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg89872] Two FindRoot questions
  • From: Aaron Fude <aaronfude at gmail.com>
  • Date: Mon, 23 Jun 2008 02:48:44 -0400 (EDT)

Hi,

These are not FindRoot questions, per se...

Here's a simple example which I want to ask three questions about:

f[k_] := x /. FindRoot[x^2 + k, {x, 0, 10}];
f[-10]
Plot[f[k], {k, -10, 10}]

First, I want the plot to only show where there exists a root.
Is the right solution to make f[] return Null?
How do I make f[] return Null? (Is there a way to "catch" the
warnings?)

Finally, I need to solve my equations to 20 digits. How do I do that?
I've read about Accuracy and Precision but it didn't help.

Thanks!


  • Prev by Date: Built-in Cross is slow
  • Next by Date: strange behaviour of background color in Panel[]
  • Previous by thread: Built-in Cross is slow
  • Next by thread: Re: Two FindRoot questions