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Re: Problem: is not a list of numbers with dimensions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg88494] Re: Problem: is not a list of numbers with dimensions
  • From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
  • Date: Tue, 6 May 2008 06:44:48 -0400 (EDT)
  • Organization: The Open University, Milton Keynes, UK
  • References: <fvmn0l$8j1$1@smc.vnet.net>

Fikri Serdar GOKHAN wrote:

> When run the below code,
> 
> A=1*10^(-4);
> 
> k=2/3;
> 
> g=1.12*10^(-11);
> 
> Attenuation= 0.23026*0.475*10^(-3);
> 
> L=7200;
> 
> Leff=(1-exp[-Attenuation*L])/Attenuation;
==========^^^
Must be Exp

> FindRoot[x-A*exp[k*g*x*Leff-Attenuation*L],{x,0}]
===============^^^
Must be Exp


> It executes the below solution,
> 
> FindRoot::nlnum: The function value {0.-0.0001 exp[-0.787489+0. \
> 
> (1.+Times[<<2>>])]} is not a list of numbers with dimensions {1} at \
> 
> {x} = {0.}.
> 
> I need your help about numerical and Alpha_numeric solution of this problem.
> 
> f(x)= x-A*exp[k*g*x*Leff-Attenuation*L
============^^^
Must be Exp

Hi Serdar,

You just made a typo when writing the exponential function. Keep in mind 
that every function names starts with a capital letter, i.e. *Exp* and 
not exp.

In[1]:= A = 1*10^(-4);

k = 2/3;

g = 1.12*10^(-11);

Attenuation = 0.23026*0.475*10^(-3);

L = 7200;

Leff = (1 - Exp[-Attenuation*L])/Attenuation;

FindRoot[x - A*Exp[k*g*x*Leff - Attenuation*L], {x, 0}]

Out[7]= {x -> 0.0000454986}

Regards,
-- Jean-Marc


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