Secondary Variables dialog.

The Secondary Variables dialog allows you to specify values for symbolic names in an expression, and iterate the values of those variables if you desire.

For example, if you create a quadratic equation in its generic form (a*x^2 + b*x + c), you can select the symbolic names a.b and c in this dialog, and assign values to them. Also, you can specify that these value are incremented by a fixed amount after each curve is plotted and produce a multiple-trace graph.

The dialog includes a button which allows you to automatically colour each trace differently (on colour Macs only). Any alphabetic names are permitted in an expression provided they are not the same as a built-in operator, such as sin, cos, etc.