Manual

Geometry 163
Rotation A rotation is a mapping that
rotates each point by a fixed
angle around a center point.
The angle is defined using
the angle() command,
with the vertex of the angle
as the first argument.
Suppose you wish to rotate
the square (GC) around point K (GK) through
∡ LKM in the
figure to the right.
1. Press
Y and tap .
2. Tap and select Transform > Rotation.
rotation() appears on the entry line.
3. Between the
parentheses, enter:
GK,angle(GK,GL,GM
),GC
4. Press
E or tap
.
5. Press
P to return to
Plot view to see the rotated square.
More
Projection A projection is a mapping of one or more points onto an
object such that the line passing through the point and its
image is perpendicular to the object at the image point.
1. Ta p a n d s e l e c t Projection.
2. Tap the object onto which points are to be projected and
press
E.
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