HP Prime Graphing Wireless Calculator - Manual (Page 40)

36 Geometry
3. Tap the point that is to be projected and press E .
Note the new point added to the target object.
Inversion An inversion is a mapping involving a center point and a
scale factor. Specifically, the inversion of point A through
center C, with scale factor k, maps A onto A’, such that A’ is
on line CA and CA*CA’=k, where CA and CA’ denote the
lengths of the corresponding segments. If k=1, then the
lengths CA and CA’ are reciprocals.
Suppose you wish to find the inversion of point B with respect
to point A.
1. Tap ,
tap Transform, and select Inversion.
2. Tap point A and press E .
3. Enter the inversion ratio—use the default value of 1—and
press E .
4. Tap point B and press
E .
In the figure, point C is
the inversion of point B
in respect to point A.
Reciprocation A reciprocation is a special case of inversion involving circles.
A reciprocation with respect to a circle transforms each point
in the plane into its polar line. Conversely, the reciprocation
with respect to a circle maps each line in the plane into its
pole.
1. Tap ,
tap Transform, and select
Reciprocation.
2. Tap the circle and press E .