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)

**Follow-Ups**:**Re: Fitting a inverse function from complicated integral***From:*Darren Glosemeyer <darreng@wolfram.com>

**Re: Fitting a inverse function from complicated integral***From:*Daniel Lichtblau <danl@wolfram.com>