HP Prime Graphing NW280AAABA manual Element 0 . . Notice

Erase Trace	Erases all trace lines, but leaves the definition of the trace
	points in Symbolic view. While a Trace definition is still in
	Symbolic view, if you move the point again, a new trace line
	is created.
Center	Tap a circle and press E. A point is created at the
	center of the circle.
Element 0 .. 1	Element 0 .. 1 has a number of uses. You can use it to
	place a constrained point on a object (whether previously
	created or not). For example, if in Symbolic view you define
	GA as element(circle(),2)), go to Plot view, turn on
	tracing, select GA and move it, you will see that GA is
	constrained to move in a circle centered on the origin and of
	radius 2.
	You can also use Element
	0 .. 1 to generate values
	that can then be used as
	coefficients in functions you
	subsequently plot. For
	example, in Plot view select
	Element 0 .. 1. Notice
	that a label is added to the
	screen—GA, for example—and given a value of 0.5. You can
	now use that label as a coefficient in a function to be plotted.
	For example, you could choose Curve > Plot > Function
	and define a function as GA*x2–7. A plot of 0.5x2–7 appears
	in Plot view. Now select the label (GA, in this example) and
	press E. An interval bar appears on the screen. Tap
	anywhere along the interval bar (or press <or >). The
	value of GA—and the shape of the graph—change to match
	the value along the at which you tapped.
Intersections	Tap one object other than a point and press E. Tap
	another object and press E. The point(s) where the two
	objects intersect are created and named. Note that an
	intersections object is created in Symbolic view even if the two
	objects selected do not intersect.
Random pts	Displays a palette for you to choose to add 1, 2, 3, or 4
	points. The points are placed randomly.

Geometry 155