himpunan penyelesaian persamaan 2cos2xsinx - cos2x = 0 dalam interval 0 ≤ x ≤ π adalah

2cos2xsinx - cos2x = 0
cos2x(2sinx - 1) = 0
cos2x = 0 atau 2sinx - 1 = 0

cos2x = 0
cos2x = cos90°
2x = 90° + k . 360°
  x = 45° + k . 180°
  x = 45°, 225°
2x = -90° + k . 360°
  x = -45° + k . 360°
  x = 315°

2sinx - 1 = 0
2sinx = 1
sinx = 1/2
sinx = sin30°
x = 30° + k . 360°
x = 30°
x = (180° - 30°) + k . 360°
x = 150° + k . 360°
x = 150°

HP = {30°, 45°, 150, 225°, 315°}

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