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Unit 4: Intro to Trigonometry. Trigonometry The study of triangles and the relationships between their sides and angles.
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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. terminal side A positive angle is described by starting at the initial side and rotating counterclockwise to the terminal side (angle ). vertex initial side A negative angle is described by rotating clockwise (angle ).
90 Angles can be larger than 360º by simply wrapping around the quadrants again. (450º, 540º, 630º, 720º, etc.) I II 360 180 III I 270 II -270 I II IV III -360 -180 IV III -90 Depending upon the degree measure of the angle, the terminal side can land in one of the four quadrants.
Name the quadrant of the terminal side. • 140o 7) 80o • 315o 8) -475o • -168o 9) -25o • 475o 10) 1030o • -340o 11) -1030o • 670o 12) -225o
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 are also several other angles that are coterminal to a .
Example: 35 + 360 = 395º • = 35º 35 – 360 = -325º Both are coterminal angles to a Find a negative and positive coterminal angle to -425o To find a coterminal angle: add or subtract 360º (or any multiple of 360o) to the given angle a.
Find one positive and one negative coterminal angle for each angle below. • 140o 7) 80o • 315o 8) -475o • -168o 9) -25o • 475o 10) 1030o • -340o 11) -1030o • 670o 12) -225o