curve fitting models-excel

huangyhg

curve fitting models-excel
does anybody have a source of good curve fitting tools that could be used in excel (or similar).  i have table curve 2d and 3d, but not for the most recent version of windows, and as such, i can't use them (despite their ease of use).
any ideas out there (i.e. without paying $500...again).
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this question comes up from time to time in the "engineering spreadsheets" forum (and elsewhere).  see, for example, threads:
   724-97493
   770-82803
   770-142106
if you need to do a lot of curve fitting, a specialised tool would be best.  if your need is either only occasional or particularly exotic, then excel can probably do the job (but at a cost of considerably more time for each curve).
excel already has curve fitting tools such as polynomials and log. if you want more specialised fitting curves such as trigonometric curves then look at the basics of least squares regression and derive the coefficients you'll need from first principles.
corus
an extension to corus:... and fourier transformation.
m777182
look at the linest function.  it can do a lot more than just linear equations.  i can find the coefficients of polynomials and non-linear equations too.  i think linest is an add on so you may have to install it off your office cd.
guys,
i heard about minitab and mathcad. do this have curve fitting features?
mathcad -- yes
ttfn
minitab can do it, but i can't re  
i found a site that can do curve fitting for more diffciult data. it's on nlreg.com. the price is $140 but you can download a trial version for 30 days, allowing only 50 data points. failing that, try
i don't do much curve fitting, but i have had a lot of luck with a program called curveexpert1.3
you can download it here:
the website i just posted looks like it may charge you to download, but i am positive that i downloaded it for free.  i'm sure it's out there somewhere  
minitab does have curve fitting and its real simple to do
you could use origin from originlab (