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Non Linear fit problem

• To: mathgroup at smc.vnet.net
• Subject: [mg67799] Non Linear fit problem
• From: "Raj" <rajanikanth at gmail.com>
• Date: Sat, 8 Jul 2006 04:56:03 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

I have a problem of fitting two temperature lists to an error
function. The physical description of the problem is as follows:

t1 is a list of temperatures on the surface of the soil and t2 is the
list of temperatures at a certain depth (say x).
We know that the dependence of t2 on t1 is as

t2 = t1 Erfc[x/(2 sqrt(k)]

 where x is the depth at which t2 is measured and k is the constant of
diffusivity.

When I plot the two temperatures, I can see that t2(temperature at a
depth) lags behind t1 by a certain time.
 My problem is to find the temperature at any depth given the
temperature at the surface (t1). Is there a way in Mathematica to find
k such that t2 and t1 have a close fit?


Thanks,

Raj

• Follow-Ups:
  • Re: Non Linear fit problem
    • From: Mary Beth Mulcahy <Mary.Mulcahy@colorado.edu>