7. Determine precise values for the following: . sin (-30) . COS (-60) o tan (-450) 8. Determine precise values for the following: o sin (-210) . COS (300) . tan (-300) 9. Use special triangles to show that the following are true: . sin (2250) = sin (-459) . COS (30) = cos (-30) . tan (-609) = tan (120) 10. For 120, show that tan T = sin T/cos T. 11. Express each of the following in a simpler form using one of the given identities: 0 1 - sin-T . tan T - sec T 12. Prove the following identities: . cotT sinT = COST o sin T sec ? T = sec ? T - 1