# 15.3.4.4.11 The Integrand Page

This page is available when Include Integration During Fitting is selected in the Name and Type page. It is used to define the expression of the integrand, which will be used in the fitting function. The integrand should include the name of the function, the integration variable (one dimension supported, so only one integration variable), and arguments (optional).

## Dialog Box Controls

 Integrand Name Specify a name for the integrand you want to define. Specify the integration variable. Specify the arguments used in the defined integrand, separating each argument with a comma. If no arguments, this can be empty. After specifying the Integrand Name, Integration Variable and Arguments, the LabTalk function prototype of this integrand is shown at the top of the Integrand Function Body box. Provide the integrand expression here, with the return keyword, to complete the definition of the integrand.