HP Prime Graphing Calculator - Manual (Page 192)

188 Geometry
is_rectangle
Tests whether or not a set of four points are vertices of a
rectangle. Returns 0 if they are not, 1 if they are, and 2 if they
are vertices of a square.
is_rectangle(point1, point2, point3, point4)
Examples:
is_rectangle(point(0,0), point(4,2),
point(2,6), point(-2,4)) returns 2.
With a set of only three points as argument, tests whether or
not they are vertices of a right triangle. Returns 0 if they are
not. If they are, returns the number order of the common point
of the two perpendicular sides (1, 2, or 3).
is_rectangle(point(0,0), point(4,2),
point(2,6)) returns 2.
is_square
Tests whether or not a set of four points are vertices of a
square. Returns 1 if they are and 0 otherwise.
is_square(point1, point2, point3, point4)
Example:
is_square(point(0,0), point(4,2),
point(2,6), point(-2,4)) returns 1.
Other Geometry functions
The following functions are not available from a menu in the
Geometry app, but are available from the Catlg menu.
convexhull
Returns a vector containing the points that serve as the convex
hull for a given set of points.
convexhull(point1, point2, …, pointn)
harmonic_conjugate
Returns the harmonic conjugate of 3 points. Specifically,
returns the harmonic conjugate of point3 with respect to
point1 and point2. Also accepts three parallel or concurrent