Unit Circle: Complementary Angles
- Brian Sterr
- Angles, Circle, Unit Circle
This sketch shows the relationship between an angle and its complement, . Drag around the circle and notice what happens to . How are the trigonometric ratios of the angles related?
What is the geometric relationship between and ?
The coordinates of are . From the relationship described in question 1, what are the coordinates of ?
Since is a point on the unit circle corresponding to the angle in standard position, it has coordinates:
Therefore, for any angle , we have: