Trigonometry
posted by Cynthia .
Solve cos 2x – 3sin x cos 2x = 0 for the principal value(s) to
two decimal places.
Please explain.

cos2x (1  3sinx) = 0
cos2x = 0 or sinx = 1/3
cos 2x = 0:
2x = k*pi/2 where k is an integer
x = pi/4, 3pi/4, 5pi/4, 7pi/4
sinx = 1/3:
x = 0.34 or pi0.34