HP Prime Graphing Wireless Calculator - Manual (Page 62)

58 Geometry
Examples:
If GA is defined to be the unit circle, then area(GA) returns
π.
area(4-x^2/4, -4,4) returns 14.666…
Angle
Returns the measure of a directed angle. The first point is
taken as the vertex of the angle as the next two points in order
give the measure and sign.
angle(vertex, point2, point3)
Example:
angle(GA, GB, GC) returns the measure of ∡ BAC.
Arc Length
Returns the length of the arc of a curve between two points on
the curve. The curve is an expression, the independent
variable is declared, and the two points are defined by values
of the independent variable.
This command can also accept a parametric definition of a
curve. In this case, the expression is a list of 2 expressions (the
first for x and the second for y) in terms of a third independent
variable.
arcLen(expr, real1, real2)
Examples:
arcLen(x^2, x, –2, 2) returns 9.29….
arcLen({sin(t), cos(t)}, t, 0, π/2) returns
1.57…
Tests
Collinear
Takes a set of points as argument and tests whether or not they
are collinear. Returns 1 if the points are collinear and 0
otherwise.
is_collinear(point1, point2, …, pointn)
Example:
is_collinear(point(0,0), point(5,0),
point(6,1)) returns 0