Learning Resources

Investigation 6: Coordinates of Points Under Various Rotations

Step E

• This is the key step in the process of the Investigation, as you are now developing the general rotational matrix.
• Remember: The x-coordinate of a point on the unit circle represents the cosine of the angle of rotation, and the y-coordinate represents its sine value. In other words, coordinates can be represented by the matrix .
• Simplify the trigonometric expressions as much as possible to arrive at a matrix in simplest form.
• You will need to refer to the cofunctions previously developed in Investigation 2 of Section 4.1.