Non-linear Curve Fitting

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Non-linear Curve Fitting*From*: David Elbert <ELBERT at midd.bitnet>*Date*: Wed, 22 Apr 1992 17:43 EST

Folks- I have had great success using the Mma "Fit[]" routine. I was recently asked, however, if I could fit some data pairs to an expression like: y=a(Tanh[b x]} This involves fitting nonlinear coefficients and isn't documented in the BIG BOOK. Is there, in fact, a way to fit to this "b" parameter. It seems that it is a much harder problem than simple fits and would require an iterative approach. Perhaps it isn't possible with the built-ins and someone else has a package available? I've been told that it is easy in the math and plotting package known as "Igor" on the Mac...isn't that enough of a gauntlet to make someone want to show me how to do this?? Thanks- David Elbert Dept. of Geology Middlebury College MIddlebury , VT 05753 (802)388 3711 x5652 Elbert at midd.bitnet