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From: "Richard " <lesricains@PleaseNoSpam.gmail.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: exponential fitting?
Date: Fri, 26 Sep 2008 17:41:02 +0000 (UTC)
Organization: Sandia National Laboratories
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Using the curve fitting toolbox, an exponential model of the form
a*exp(b*x)+c*exp(d*x)

"looks" like it fits well enough.



"Mario " <nospam@yahoo.com> wrote in message <gbj5k4$5fa$1@fred.mathworks.com>...
> Hi..
> I'm dealing with this kind of data
>  
> x=[527.3756  546.1192  564.9728  586.4216  608.2959  630.5845  652.8730  674.8214  697.0359]
> 
> y=[193  204.1192  214.9728  219  222  224 222 219.1786  217]
> 
> and i would like to fit a*(1-exp(b*x))   (because i think it's the best curve that fits these points) and i tried to do it but i didn't get a good fit! What am i doing wrong?
> I even tried to scale the data in order to place the first point in [0,0] but it didn't work as i expected (the exponential curve fit the points after it grows, so it fits the point with a line almost)
> 
> Hope you can help me! 
> Regards,
> 
> Mario