A)
Using the unit circle, for the cos function to be positive, angle A must lie in either <u>quadrant I or quadrant IV</u>
B)
Using the unit circle, If the sine is negative, angle A must lie in either quadrant III or quadrant IV. Since we know that the cosine is positive, this only leaves <u>quadrant IV</u>
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D)
cos = adj/hyp
Using Pythagorean theorem,
b = ±5 (we know its -5 since we know sinA is negative)
this means that the x coord is 12, and the y coord is -5
any proportion of these two numbers would work as an answer
e.g. <u>(12, -5), (24,-10), (12/13, -5/13),</u> are all valid answers
E)
sinA = opp/hyp
<u>sinA = -5/13</u>
tanA = opp/adj
<u>tanA = -5/12</u>