Question: What is the value of cos(2x) if sin x = 1/2?
Options:
Correct Answer: 1/2
Solution:
Using the double angle formula cos(2x) = 1 - 2sin^2 x. Since sin x = 1/2, we have cos(2x) = 1 - 2*(1/2)^2 = 1 - 2*(1/4) = 1 - 1/2 = 1/2.