4 cos^2x-1=0
cos^2 x = 1/4
cosx = ± 1/2
In I x = 60
in II , x = 180-60 = 120
in III, x = 180+60 = 240
in IV , x = 360-60 = 300
find, to the nearest degree, the solution set of 4 cos^2x-1=0 in the intervak between )degrees and 360degrees.
1 answer