posted by Stephanie on .
Evaluate each value as a trigonometric function of an angle in Quadrant 1.
#1 cos (27pi/8)
27 pi/8 = 3 pi + 3 pi/8
that is 180 degrees + 67.5 degrees
that is in quadrant 3 where cos is negative
-cos 3 pi/8 radians
-cos 67.5 degrees