Lecture 21 (Geometry) Trigonometric Functions and The Unit Circle

On the unit circle, cosine of an angle θ is defined to be:

1. A.The y-coordinate of the point at angle θ.
2. B.The x-coordinate of the point at angle θ.
3. C.The arc length swept out by the angle θ.
4. D.The slope of the radius at angle θ.