Arc Command

Arc( <Circle>, <Point M >, <Point N> ): Returns the directed arc (counterclockwise) of the given circle, with endpoints M and N.
Arc( <Ellipse>, <Point M>, <Point N> ): Returns the directed arc (counterclockwise) of the given ellipse, with endpoints M and N.
Arc( <Circle>, <Parameter Value>, <Parameter Value> ): Returns the circle arc of the given circle, whose endpoints are identified by the specified values of the parameter.

Internally the following parametric forms are used:Circle: (r cos(t), r sin(t)) where r is the circle’s radius.

Arc( <Ellipse>, <Parameter Value>, <Parameter Value> ): Returns the circle arc of the given ellipse, whose endpoints are identified by the specified values of the parameter.

Internally the following parametric forms are used:Ellipse: (a cos(t), b sin(t)) where a and b are the lengths of the semimajor and semiminor axes.