Origin Version (Select Help-->About Origin): Operating System: Windows XP In Nonlinear curve fitting section, an user can define a function. Can an user-defined function contain derivation? If yes, how can I do it?
In the Origin 7.5 Help File, look at the topic: Analysis:Curve Fitting>Then NLSF Advanced Fitting Tool>User-Defined Fitting Functions> and then click on the last link: "The Derivatives Check Box" to see an example.