Question

Tolong di jawab
Soal matematika sbmptn saintek

Answer 1

Trigo

Intrval [0, 2pi]

2 cos² x ≤ 3 - 3 cos 2x

2cos² x - 1 ≤ 3 - 3 cos 2x - 1

(2cos² x -1 ) + 3 cos 2x ≤ 3 - 1

cos 2x + 3 cos 2x ≤ 2

4 cos 2x ≤ 2

cos 2x ≤ 2/4

cos 2x ≤ 1/2

...

cos 2x ≤ 1/2

cos 2x ≤ cos 60

2x = 60 + k. 360 atau 2x = -60 + k. 360

x = 30 + k. 180 atau x = - 30 + k. 180

k = 0,1,2,3....

k = 0--> x = 30 , x = - 30

k = 1 --> x = 210 atau x = 150

k = 2--> x = 390 atau x = 330

x = (30, 150) U (210, 330)

jumlahkan = 720 = 720/180 = 4 π