Footprints

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Stage: 5 Challenge Level: Challenge Level:2 Challenge Level:2

To find the formula for this combinaton of three reflections requires very little knowledge of complex numbers. All you have to do is to combine the complex maps as you combine functions.. The example shows the power of complex numbers as a tool for working with transformations in the plane.

In the problem Complex Rotations you see another examle of using complex numbers for work with transformations.

The problem The Matrix introduces the idea of using matrices for work with transformations.The use of 2 by 2 matrices is efficient for transformations which have a fixed point, usually taken to be the origin. Complex numbers have the advantage that they also handle translations.

The problems Rots and Refs and Reflect Again are examples of the use of matrices for work with transformations.

This problem is about combinations of reflections. The problem Reflect Again uses matrices to show that the combination of two reflections in intersecting mirror lines gives a rotation.


Published May 2006.