Question

Pertannyaaan
2 cos 2x - 7 sin (90-x) +3 =0 adalah
pada interval 0,360

Answer 1

Sin (90 - a) = cos a

2 sin² x - 7 cos x + 3 = 0
(2 sin x - 1)(sin x - 3) = 0
2 sin x - 1 = 0 atau sin x - 3 = 0

2 sin x - 1 = 0
2 sin x = 1
sin x = 1/2
sin x = sin 30
x = 30 + k.360
k = 0, x = 30
atau
x = (180 - 30) + k.360
k = 0, x = 150

HP : {30, 150}