2.2 Trigonometric Ratios with Obtuse Angles with ink
February 29, 2016
Unit 2: Trigonometry
2.2 Trigonometric Ratios with Obtuse Angles
Standard Position
• An angle in standard position is measured counter­
clockwise about the origin from the positive x­axis on the Cartesian plane.
• To determine the primary trigonometric ratios, choose any point, P, on the terminal arm and draw a vertical line from P to the x­axis to form a right triangle. r
y
x
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2.2 Trigonometric Ratios with Obtuse Angles with ink
February 29, 2016
Acute Angles in Standard Position
Ex:
Obtuse Angles in Standard Position
An obtuse angle is greater than 900. The terminal arm for an obtuse angle lies in the second quadrant. Ex:
Notice that the cosine and tangent ratios are negative, while the sine ratio is positive.
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2.2 Trigonometric Ratios with Obtuse Angles with ink
February 29, 2016
Ex: Work: p. 93­95, #1,3,4,11,12
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