Jawab:
Hp = {210°, 270°, 330°}
Tidak ada yg benar

Penjelasan dengan langkah-langkah:
2sin²x + 3sinx + 1 = 0   0 ≤ x ≤ 360°
u = sin(x)
2u² + 3u + 1 = 0
(1/2)(2u+...)(2u+...) = 0
----------------------------------------
cari 2 bilangan yg dikali = 2
ditambah = 3
2 bilangan tsb = 1dan2
-----------------------------------
(1/2)(2u+1)(2u+2) = 0
(2u+1)((1/2)(2u+2)) = 0
maka
(2u+1)(u+1) = 0
u = -1/2 dan -1
sin(x) = -1/2
x = (180+30), x = (360-30)
x = 210°, 330°
dan sin(x) = -1
x = 180+90
x = 270°
Hp = {210°, 270°, 330°}

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