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
Verified answer
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°}