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

*To*: mathgroup at smc.vnet.net*Subject*: [mg88507] Re: [mg88450] Problem: is not a list of numbers with dimensions*From*: "W_Craig Carter" <ccarter at mit.edu>*Date*: Tue, 6 May 2008 06:47:12 -0400 (EDT)*References*: <200805051016.GAA08633@smc.vnet.net>

Hello Fikri, When beginning to use Mathematica, it is probably a good idea to leave off the trailing ";" In this way, you will quickly see the syntax errors---this will lead you to start exploring some of the documentation. For this example, I would say this would be a good paradigm for those just getting started: (*Build up expressions with symbols, not numbers*) Leff = (1 - Exp[-Attenuation*L])/Attenuation GenExpr = x - A*Exp[k*g*x*Leff - Attenuation*L] (*use replace to create a particular instance of your expression*) Expr = GenExpr /. {A -> 10^(-4), k -> 2/3, g -> 1.12*10^(-11), L -> 7200, Attenuation -> 0.23026*0.475*10^(-3) } (*visualize what you intend to do*) Plot[Expr, {x, -1, 1}] (*Check the documentation and (if everything is fine) get your answer*) FindRoot[Expr, {x, 0}] On Mon, May 5, 2008 at 6:16 AM, Fikri Serdar GOKHAN <fsgokhan at gmail.com> 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; > > > > FindRoot[x-A*exp[k*g*x*Leff-Attenuation*L],{x,0}] > > > > 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 > > > > Serdar > > > -- W. Craig Carter

**References**:**Problem: is not a list of numbers with dimensions***From:*"Fikri Serdar GOKHAN" <fsgokhan@gmail.com>