General Equations

General (nonlinear) equations are defined as equations that are nonlinear in the parameters, or are a combination of linear and nonlinear in the parameters. For example, the exponential library equations are nonlinear. The General Equations pane is briefly described below.

• Independent variable -- Symbol representing the independent (predictor) variable. The default symbol is x.
• Equation -- Symbol representing the dependent (response) variable followed by the general equation. As you type in the terms of the equation, the unknown coefficients, associated starting values, and constraints automatically populate the table. By default, the starting values are randomly selected on the interval [0,1] and are unconstrained.

• You can immediately change the default starting values and constraints in this table, or you can change them later using the Fit Options GUI.

• Equation name -- The name of the equation. By default, the name is automatically updated to be identical to the custom equation given by Equation. If you override the default, the name is no longer automatically updated.

To save custom equations for later use, you should save the curve fitting session.