2Var app - user defined fit

[Han]

Please read: http://hpmuseum.org/forum/thread-1138.html

In sum, a user-defined fit is not the same as one of the built-in fits. A user-defined fit merely allows the user to take an already-existing fit and make minor adjustments to the formula (hence it becomes "user-defined"). Think of it as a means to tweak an existing formula obtained from one of the built-in fits in order to obtain a function that more closely resembles the data.