Rotation Matrices

Main Concepts

Transformations in the plane:

Scaling, Rotation, Shear


30-40 minutes in class

Summary of Activity

Any smartphone allows us to rotate and zoom on pictures. How is it done? This activity presents some basic applications of scaling and rotation using linear algebra. The third part is more realistic and closer to the actual methods employed in softwares and apps, as described on the webpage linked above.

Notes and Insights

This activity can be used in Precalculus, particularly the first two pages — the third page is more technical. It’s nice if the hand-out is printed in color. I always insist that students actually draw the mouse and cup. It makes the experience a little bit more memorable.