First Quadrant: 0o to 90o, All trig ratios are positive, Reference angle, 30o, cos 60o = 1/2 (Ə < 180o), Second Quadrant: 90o to 180o, Only sin is positive, 135o, sin Ə = 1/2 (Ə > 90o), 180o + Ə, Third Quadrant: 180o to 270o, Only tan is positive, 225o, sin Ə = -1/2 (Ə < 270o), Ə - 180o, Fourth Quadrant: 270o to 3600, Only cos is positive, 330o, tan Ə = -1 (Ə > 180o), 360o - Ə,

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