Unit 4 Intro to Trigonometry Trigonometry The study
- Slides: 8
Unit 4: Intro to Trigonometry
Trigonometry The study of triangles and the relationships between their sides and angles
Let’s look at an angle in standard position, where the initial side is ALWAYS on the positive x-axis and the vertex is at the origin. The terminal side can be anywhere and defines the angle. A positive angle is described by starting at the initial side and rotating counterclockwise to the terminal side (angle ). A negative angle is described by rotating clockwise (angle ). terminal side vertex initial side
Depending upon the degree measure of the angle, the terminal side can land in one of the four quadrants. II I III IV Angles can be larger than 360º by simply wrapping around the quadrants again. (450º, 540º, 630º, 720º, etc. ) -270 90 II I -360 -180 360 180 I II IV III -90 III 270
Name the quadrant of the terminal side. 1) 2) 3) 4) 5) 6) 140 o 315 o -168 o 475 o -340 o 670 o 7) 80 o 8) -475 o 9) -25 o 10) 1030 o 11) -1030 o 12) -225 o
Coterminal Angles are angles that share the same terminal side, but have different angle measures. Angles and are coterminal since they share the same sides. There also several other angles that are coterminal to .
To find a coterminal angle: add or subtract 360º (or any multiple of 360 o) to the given angle . Example: = 35º 35 + 360 = 395º 35 – 360 = -325º Both are coterminal angles to Find a negative and positive coterminal angle to -425 o
Find one positive and one negative coterminal angle for each angle below. 1) 140 o 7) 80 o 2) 315 o 8) -475 o 3) -168 o 9) -25 o 4) 475 o 10) 1030 o 5) -340 o 11) -1030 o 6) 670 o 12) -225 o