Find points on the unit circle determined by real numbers.
Convert between radian measure and degree measure; find coterminal, complementary, and supplementary angles.
Find the length of an arc of a circle; find the measure of a central angle of a circle.
Convert between linear speed and angular speed.
Another useful unit of angle measure is called a radian. To introduce radian measure, we use a circle centered at the origin with a radius of length 1. Such a circle is called a unit circle. Its equation is .
The circumference ...