Question 629449
solve for each question for 0 lesser than or equal to theta lesser or equal to 360 degrees. 
a. 2 cos theta - square root of 3 = 0
2cosx-√3=0
cosx=√3/2
x=30º and 330º (in quadrants I and IV where cos>0)
..
b. cos^2x+ 3 cos x +2 =0
(cosx+2)(cosx+1)=0
cosx+2=0
cosx=-2 (reject, -1 < x < 1)
or
cosx+1=0
cosx=-1
x=180º