Question

The sound wave of two music notes can be represented by the function y = 2sin2x and y = −sin x, where x represents the time since the note is played. At what times will the frequencies of the sound waves be the same in the interval [0°, 360°)?

x = 0°, 30°, 90°, 150°
x = 0°, 90°, 210°, 330°
x = 30°, 150°, 180°, 270°
x = 180°, 210°, 270°, 330°

Answer 1

x = 0°, 180°, 210°, 330°

If you were to graph the two functions those would be the intersection points (after converting from radians to degrees)