III. Use a double angle or half angle identity to find each of the following. Write the identity then show work, 7. Given cos 20 = 1 and 270 < 0 < 360, find sin 8. 8. Given cos A = V/ and sin 80, find cos 20. 3 5 9. Find the exact value of sin 15 II. Solve each equation for exact solutions over the interval [0, 27). 11. Sin x= V 10. Cos 0 = 0 13. 4 cos 0 -3 = 0 15, sin x (2cosx+1)=0 Cot x = -1 14 3 ta 0 = | 12. 16. cscxcscx - 2 = 0