
Inversion
An inversion is a mapping involving a center point and a scale factor. Specically, 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 nd the inversion of point B with respect to point A.
1.
Tap , tap Transform, and select Inversion.
2.
Tap point B and press .
3.
Enter the inversion ratio—use the default value of 1—and press .
4.
Tap point A and press .
In the gure, 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 .
3.
Tap a point and press to see its polar line.
Plot view: Cmds menu 185
Komentarze do niniejszej Instrukcji