Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2008

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

Search the Archive

Fitting a inverse function from complicated integral

  • To: mathgroup at smc.vnet.net
  • Subject: [mg87210] Fitting a inverse function from complicated integral
  • From: tibor dubaj <t.dubaj at gmail.com>
  • Date: Fri, 4 Apr 2008 02:57:54 -0500 (EST)

Dear Group,

I need to Fit this experimental data {x, OOT}:

data = {
{1, 444.6},
{3, 455.15},
{5, 464.81},
{7, 467.79},
{10, 469.01},
{15, 480.28}}

But there is a big problem with model equation:

x = Integrate[A*Exp[-B/T], {T, 0, OOT}, Assumptions -> A > 0 && B > 0
&& OOT > 0]

So, after integration:

x = A (Exp[-B/OOT] OOT - B Gamma[0, B/OOT])

I need to obtain a INVERSE function, i.e. OOT = f(x) and then find
(e.g. via FindFit) best fitting parameters A, B.

I have tried Series expansion, PadeApproximant etc., but every
approximation of mentioned
model contain A*Exp[-B/T], so I cannot find inverse function.

Can Somebody help me with this problem?


*****************
$Version
6.0 for Microsoft Windows (32-bit) (February 7, 2008)



  • Prev by Date: Re: What is @@@?
  • Next by Date: Re: solving a system of polynomial equations
  • Previous by thread: Re: Solve inconsistant actions?
  • Next by thread: Re: Fitting a inverse function from complicated integral