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Trig Functions of Angles

Sol 1 The reference angle for is . Since the sine is positive in Quadrant II, .

Sol 2 The reference angle for is . Since the cosine is negative in Quadrant III, .

Sol 3 The reference angle for is . Since the tangent is negative in Quadrant II, .

Sol 4 The reference angle for is . Since the cosine is positive in Quadrant IV, .

Sol 5 The reference angle for is . Since and the cosine is negative in Quadrant III, and .

Sol 6 The reference angle for is . Since and the tangent is negative in Quadrant II, and .

Sol 7 The reference angle for is . Since the tangent is positive in Quadrant III, .

Sol 8 The reference angle for is . Since and the sine is negative in Quadrant IV, and .

Sol 9 Since ,

and .

Sol 10 Since , subtracting off a multiple of gives ; so . Since the reference angle for is , and since the sine is positive in Quadrant II, .

Sol 11 Since , subtracting off a multiple of gives ; so . Since the reference angle for is , and since the cosine is positive in Quadrant IV, .

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Lawrence Marx 2002-07-14