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Applying lists to FindRoot of a NIntegrate function

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  • Subject: [mg101284] Applying lists to FindRoot of a NIntegrate function
  • From: Christian Schneider <kofferpc at>
  • Date: Tue, 30 Jun 2009 06:31:56 -0400 (EDT)

Dear members of the mathgroup email group,

I have serious difficulties in solving the following problem in Mathematica 
(v.6) and would very appreciate it if anyone could give me a helping hand with 

To start with, I have a list of data points {{x[[i]],y[[i]]}}. 

Also, I have the function W. W consists of two single functions f[r] and g[r, 
x, a]: 

f[r_] = r^2+r+2/(r^2+r)

g[r_, x_, a_] = Exp[a*Exp[-x*r]]

W := NIntegrate[f[r]*g[r, x, a], {r, 0.1, 100}]

What I have given for every pair of data is W[x[[i]]] == y[[i]] (see the list 
of data points). What I do not have  is the corresponding value of a[[i]]. 

So, I want to use FindRoot to give me the value of a[[i]] for each of my data 
pairs {x[[i]],y[[i]]}.

Although I have found many examples quite similar to this problem, I have been 
unable to adjust those to work in my case.

I would be very grateful if somebody could provide me with the proper syntax 
for this.

Thanks very much in advance,


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