Algebra and Trigonometry, 5th Edition

6.4 Radians, Arc Length, and Angular Speed

• 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 $x{}^2+y{}^2=1$.

CIRCLES

REVIEW SECTION 1.1

Distances on the Unit Circle

The circumference ...