Evaluating Sine and Cosine at Other Special Angles - Concept

Concept Concept (1)

To find the value of sine and cosine at non-acute angles (from 90 to 360), first draw the angle on the unit circle and find the reference angle. A reference angle is formed by the terminal side and the x-axis and will therefore always be acute. When evaluating cosine and sine for the reference angle, determine if each value is positive or negative by identifying the quadrant the terminal side is in.

Sample Sample Problems (3)

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Evaluating Sine and Cosine at Other Special Angles - Problem 1
Problem 1
How to measure the sine and cosine of -135?.
Evaluating Sine and Cosine at Other Special Angles - Problem 2
Problem 2
How to measure the sine and cosine of 11*pi/6.
Evaluating Sine and Cosine at Other Special Angles - Problem 3
Problem 3
How to measure the sine and cosine of -5*pi/3.