User`s guide

Parametric Fitting
3-21
You create custom equations with the Create Custom Equation GUI. The GUI
contains two panes: a pane for creating linear equations and a pane for creating
general (nonlinear) equations. These panes are described below.
Linear Equations
Linear equations are defined as equations that are linear in the parameters.
For example, the polynomial library equations are linear. The Linear
Equations pane is shown below followed by a description of its parameters.
•
Independent variable — Symbol representing the independent (predictor)
variable. The default symbol is
x.
•
Equation — Symbol representing the dependent (response) variable
followed by the linear equation. The default symbol is
y.
-
Unknown Coefficients — The unknown coefficients to be determined by
the fit. The default symbols are
a, b, c, and so on.
-
Terms — Functions that depend only on the independent variable and
constants. Note that if you attempt to define a term that contains a
coefficient to be fitted, an error is returned.
-
Unknown constant coefficient — If selected, a constant term is included
in the equations to be fit. Otherwise, a constant term is not included.
-
Add a term — Add a term to the equation. An unknown coefficient is
automatically added for each new term.
-
Remove last term — Remove the last term added to the equation.