Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2011

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

Search the Archive

FindRoot with algebraic expressions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg122808] FindRoot with algebraic expressions
  • From: Mirko <dashiell at web.de>
  • Date: Fri, 11 Nov 2011 04:54:10 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com

Hi,

I was wondering how FindRoot works when trying to use a algebraic initial point.
I.e.:

FindRoot[h[theta]==0,{theta[m], ???}]
where h is function of theta, for example:
h[theta_]=1/(1-m)*theta[m]  
(notice that this is for a given m).

What should I use as a starting point?

If I just use 1 as a starting point, it returns a mistake. However, I could use the solution of a first step approximation, but it doesn't work as well. Here is what I mean:

t0=Solve[h1[theta]==0,theta[m]]

(where h1 is a different function, similar to h). 
Plugging t0 into ??? returns a mistake as well. This is probably due to the format? 
Although, even if I use

theta[m]/.Solve[h1[theta]==0,theta[m]]

and plugging theta[m] into ??? gives me a mistake.



  • Prev by Date: Re: Manipulate Slider not Moving
  • Next by Date: Re: Converting a list of strings to a single space-delimited string
  • Previous by thread: Re: AspectRatio -> 1 vs AspectRatio ->1.25
  • Next by thread: Re: FindRoot with algebraic expressions