In any equation, in addition to the pre-programmed constants such as e and pi, you can also include the free variables b, c, j, and k which you can define yourself. These parameters are effectively symbolic constants that make it easier to "play around" with the exact shape of the curve without editing the equation extensively.
The values of parameters used in each equation must be specified along with that equation, but if you don't type them in explicitly, Graphmatica will take the value(s) from the Variables Panel and insert this information in the equation for you. If you want, you can type in a value manually using a format similar to the normal domain specifier, for example:
{b: 1}
{c: -1/2}
{k: -pi/4}As usual, enclose the "domain" in curly braces. You must specify which parameter you want to set by its name (b or c) and a colon, followed by a value, which can be any expression that evaluates to a constant. You may not use other parameters either, since this could become self-referential.
Note: use the Inv key on the virtual keyboard to switch the semicolon key into a colon and back.
The special free variable a is described in Graphing Families of Functions.
You can change the value of a free variable after you have typed in equations and Graphmatica will automatically update and redraw all of the graphs using it with the new value. See Variables Panel for details.