Answer to Question #75237 in Trigonometry for Anonymous

Question

Find all solutions in the interval [0, 2π): 2cos^2(2θ)-1=0
a. π/4, 3π/4, 5π/4, 7π/4
b. π/8, 3π/8, 5π/8, 7π/8, 9π/8, 11π/8, 13π/8, 15π/8
c. π/8, π/4, 3π/8, 3π/4
d. π/2, π/4, 3π/2, 3π/4, 5π/2, 5π/4, 7π/2, 7π/4
d. none of these

Answer 1

b. π/8, 3π/8, 5π/8, 7π/8, 9π/8, 11π/8, 13π/8, 15π/8