Dont understand trigonometry? (ten points to best answer)?

Because this is a second order equation there should be 2 solutions. I can tell you that if theta = 60 deg. then another solution (not a second solution) is theta = -60 deg. The value of the cosine function is symmetrical (in other words 60 deg above and 60 deg below) across the x axis. In other words cos 60 = cos -60. The unit circle will tell you this but you should remember it. The sine function is symmetrical across the y axis.