The routine returns true if the point f or the list/set of points f is on circle c; false if it is not; and FAIL if it is unable to reach a conclusion.

In case of FAIL, if the third optional argument is given, the condition that makes f on circle c is assigned to this argument. It will be either of the form  or of the form  where expr, expr_i are Maple expressions.

The command with(geometry,IsOnCircle) allows the use of the abbreviated form of this command.

IsOnCircle:   "hint: the following conditions must be satisfied: {24/25+b^2 = 0, 13/4+a^2-4*a = 0}"