Question: What is the value of cos(2θ) if sin θ = 1/2?
Options:
Correct Answer: -1/2
Solution:
Using the double angle formula cos(2θ) = 1 - 2sin^2 θ. Here, sin θ = 1/2, so cos(2θ) = 1 - 2(1/2)^2 = 1 - 2(1/4) = 1 - 1/2 = 1/2.