This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Section 4.3 Unit Circle Trigonometry 1 Section 4.3 Trigonometric Functions of Angles An angle is formed by two rays that have a common endpoint (vertex). One ray is called the initial side and the other the terminal side . A terminal angle can lie in any quadrant, on the x-axis or y-axis. An angle is in standard position if the vertex is at the origin of the two-dimensional plane and its initial side lies along the positive x-axis. Positive angles are generated by counterclockwise rotation. Negative angles are generated by clockwise rotation. Section 4.3 Unit Circle Trigonometry 2 The Reference Angle or Reference Number Let be an angle in standard position. The reference angle associated with is the acute angle (with positive measure) formed by the x-axis and the terminal side of the angle . When radian measure is used, the reference angle is sometimes referred to as the reference number (because a radian angle measure is a real number). Example 1: Draw each angle in standard position and specify the reference angle. a. 405 o Note: Notice that in part a. 405 terminates in the same position as 45 . These type of angles are called coterminal angles . Every angle has infinitely many coterminal angles. Every angle has infinitely many coterminal angles....
View Full Document
- Fall '08