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Conjugating Transformations

Conjugating a Rotation

To determine what happens to a point, P, when we rotate it about a point, C, that is not at the origin of the Cartesian plane, O; we can first translate C to O, then rotate about O, then undo the translation. See how this works in the example below.

Conjugating a Reflection

Now, let's try using conjugation to determine what happens when we reflect over a line that does not pass through the origin.

Step 1: Translate the line to pass through the origin

Step 2: Rotate to align with the x-axis

To rotate, we use a rotation around the origin by where .

Step 3: Reflect over the x-axis

Step 4: Rotate Back

Step 5: Translate Back