Answer: 8 (The second option).
Step-by-step explanation:
1. To solve this exercise you draw a line to a point O, this lines will bisect the angle of Z∠60°. Then will obtain two into two right triangles with two angles of 30° at the point Z.
2. The lenght XY will be twice the lengt XO or YO.
3. Let's calclate XO as following:

4. Then, XY is:

Answer:
20
Step-by-step explanation:
Answer: 7/8
Cos2x has 3 formulas, Sinx is given in the question, we should use the formula with sinus. I guess that's the solution.