Detailed description

y = cos theta, points marked at (0,1), (30, 0.87), (60, 0.5), (90, 0). (120, -0.5.), (150, -0.87), (180, -1), (210, -0.87), (240, -0.5), (270, 0), (300, 0.5), (330, 087), (360, 1), range of graph from y = 1 to y= -1.