15. Choose the best answer. Use the sum and difference identities to find cos(u - 37). - cos u O COS u - tanu O tan u 16. Choose the best answer. Simplify (Use Pythagorean identities): 2 cot2 0 + 3 - csc2 0 O tan 0 + 2 O -1 O 1 O cot 2 0 + 2 O sin2 0 + 1 00:47:14