Mathematics for IGCSE & O level - Transformations (Section 7 - No. 24)
If a figure is rotated 90 degrees clockwise about the origin, what happens to a point (x,y)?
(x,y) becomes (-y,x)
(x,y) becomes (y,-x)
(x,y) becomes (y,x)
(x,y) becomes (x, -y)
解释
A clockwise 90° rotation changes (x, y) to (y, -x).