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.
