This routine tests if the given triangle ABC is equilateral. It returns true if ABC is equilateral; false if it is not; and FAIL if it is unable to reach a conclusion.

In FAIL is returned, and the optional argument is given, then the condition that makes ABC equilateral is assigned to this argument. It will be either of the form  or of the form  where expr, expri_i are maple expressions.

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

IsEquilateral:   "hint: one of the following conditions must be satisfied: {3-a^2 = 0}"