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

MathGroup Archive 2009

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

Search the Archive

Re: Can Plot, can't FindRoot - what gives?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg97730] Re: Can Plot, can't FindRoot - what gives?
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Thu, 19 Mar 2009 05:24:46 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <gpsrae$mm8$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

f[c_?NumericQ] := (s =
    NDSolve[{y'[x] == c - 1, y[0] == 0}, y, {x, 0, 2*Pi}];
   (Evaluate[y[x] /. s] /. x -> 2*Pi)[[1]])

Plot[f[c], {c, 0, 10}]
f[1]
FindRoot[f[c] == 0, {c, 1}]

gives not a single error ..

Regards
   Jens

Aaron Fude wrote:
> Hi,
> 
> Here's my code for a model problem. I do not need a solution to this
> simple problem, of course - I just need to understand why Mathematica
> is giving me an error.
> 
> f[c_] := (
>   s = NDSolve[{ y'[x] == c - 1, y[0] == 0}, y, {x, 0, 2*Pi}];
>   (Evaluate[y[x] /. s] /. x -> 2*Pi)[[1]]
>   )
> Plot[f[c], {c, 0, 10}]
> f[1]
> FindRoot[f[c] == 0, {c, 1}]
> 
> I get a series of errors, the first of which is
> NDSolve::ndnum: Encountered non-numerical value for a derivative at x
> \== 0.`
> 
> I'm on Win32 version 6.
> 
> Many thanks in advance,
> 
> Aaron
> 


  • Prev by Date: Re: Multivariate normal distribution
  • Next by Date: Incompatible units?
  • Previous by thread: Can Plot, can't FindRoot - what gives?
  • Next by thread: Re: Can Plot, can't FindRoot - what gives?