cos^2(2x) + sin 2x - 1 =0. Tentukan himpunan penyelesaian

cos²2x + sin 2x - 1 = 0
(1 - sin²2x) + sin 2x - 1 = 0
-sin²2x + sin 2x = 0
sin²2x - sin 2x = 0
sin 2x(sin 2x - 1) = 0
sin 2x = 0
sin 2x = sin 0
2x = 0
x = 0
sin 2x = sin 180
2x = 180
x = 90
sin 2x = sin 360
2x = 360
x = 180

sin 2x - 1 = 0
sin 2x = 1
sin 2x = sin 90
2x = 90
x = 45

hp {0°,45°,90°,180°}