XL-Plot Help on the web.

 
How to fit a function to a curve?

XL-Plot is a multi-purpose spreadsheet and vector-graph
program, derived from Serf, a more specific program for
electrophysiologists. Serf may be downloaded from my site
at the Institut de Pharmacologie Moléculaire et Cellulaire at
the university of Nice. If this site is not (anymore) available,
you'll find the new site by searching on AltaVista.

I'll be happy to reply to all your  questions and comments.