Help Please

Use the addition and subtraction formulas for sine, cosine and tangent to calculate the following expressions: Circle the correct choice for all questions below. [cos(x + y) + cos(x - y)] = Question 1: 2 A. cos(x) sin(y) B. cos(x) . cos(y) C. cos (x) D. sin(y) sin(r ty) + sin(x - y) Question 2: 2cost . cosy A. tan(x) B. cot(x) C. sin(x) D. cos(x) COS + D) = Question 3: 2 A. sec(x) B. tan(x) C. cos(x) D. sin(x)