If COS X = - 1/3 and x is in quadrant II, answer the following questions:
sin(x/2)
cos(x/2)
+128408 sin (x/2) = sqrt [ ( 1 - cos x) / 2 ] = [ (1 - (-1/3) ) / 2 ] = sqrt [ (4/3) / 2 ] =
sqrt [ 4/6] = sqrt (4) /sqrt (6) = 2 sqrt 6 = (2/6) sqrt 6 = sqrt 6 / 3
cos (x/2) = sqrt [ (1 + cos x) /2 ) ] = sqrt [ ( 1 + - 1/3) / 2] = sqrt [ (2/3)/2] = sqrt [ 1/3] =
sqrt ( 1 )/ sqrt (3) = sqrt (3)/3
