Jika sin(2x – 60)= -½, untuk -90°≤ x ≤ 180°, nilai x yg memenuhi adalah

Sin(2x – 60) = -1/2
sin(2x – 60) = sin (-30)
(2x – 60) = (-30) + k . 360 atau (2x – 60) = (180 – (-30)) + k . 360
2x = 30 + k . 360 ……………………. 2x = 270 + k.360
x = 15 + k . 180 ………………………….. x = 135 + k.180
k = -1 => x = -165 (TM) ………………. x = -45
k = 0 => x = 15 ………………………….. x = 135
k = 1 => x = 195 (TM) ………………… x = 315 (TM)
HP = {-45, 15, 135}
TM = tidak memenuhi