Select the Custom Function tab of the 2D Custom Function Plots dialog to access options to produce graphs based not on values of variables in a data file, but on a user-defined formula (custom function or a set of functions), for example: y = x**2 + x/2.
Name. The name of the function (if one is given) is displayed in this field. To create (and name) a new function, click the Add to list button.
Type. In the Type box, select either Function or Parametric curve. If you select Parametric Curve, Y(t)= and X(t)= edit boxes are displayed at the bottom of the tab. For more information, see Parametric Curve.
Range of X/Range of Parameter t. Specify here the range (i.e., minimum and maximum values) of the X variable for the custom function.
Add to list. If you want to create a function that can be saved and reused at a later time, click this button. The New Function dialog is displayed, in which you specify a name for the function. The function can then be selected from the Function Name Manager and edited (see Function List).
Function list. Click the Function list button to display the Function Name Manager. This dialog is used to create a new function and to edit, rename, or delete an existing function.
Function. Enter the function you want to plot in this field (or fields, if you selected Parametric curve as the Type). Note that as you type, a menu with possible characters or functions will be displayed. You can choose from any item on the menu, or type the function yourself. If you want to save this function for later use, you must add it to the function field in the Function Name Manager. It will not be automatically added for you.