12 Trigonometric Functions of Any Angle

tions of any angle, not just acute angles, (2) the sign of the trigonometric functions in each quadrant of the coordinate plane, and (3) the use of refer-ence angles which reduce the question of nding the trigonometric functions of an angle to that of nding the trigonometric functions of the special an-gles 30 ;45 ;and 60 : Let be an angle in ... ................
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