Use a half angle identity to find the exact value cos 105 Which half angle formula should be used to find the exact value of cos 105 Sele Simplify your answer including any radicals Use integers or fractions for any num A cos 105 cos B cos 105 cos cos 105 cos OD cos 105 cos 210 2 2 2 2 O O 1 cos 210 2 1 cos 1 cos 1 COS 1 cos 1 cos 2 O O O O 2 3 cos 105 2 Simplify your answer including any radicals Use integers or fractions for any nur