Question

Trigonometri kelas XI

Answer 1

Verified answer

Jawab

2 sin² (2x)  -10 sin x cos x - 3 =0
2 sin² (2x) - 5(2 sin x cos x) - 3 =0
2 sin² (2x) - 5 sin (2x)  - 3= 0
sin 2x = y
2y² - 5y - 3 =0
(2y +1)(y - 3) =0
y = -1/2  atau y = 3
sin 2x = -1/2  atau sin 2x = 3 (tidak memenuhi)

sin 2x = -1/2 = sin 210
2x = 210
x = 105

sin 2x = -1/2 = sin 330
2x = 330
x = 165

x = (105, 165)