himpunan penyelesaian dari persamaan trigometri cos 2x = cos 60°

maaf jika salah,,,....

cos2x = cos60
2x = 60
x = 60/2
x = 30°

(ingat cos 60 = cos (360 - 60) = cos300)

cos2x = cos300
2x = 300
x= 300/2
x = 150°

cos60 = cos(360 + 60) = cos420

cos2x = cos420
2x = 420
x = 420/2
x = 240°

cos60 = cos(720-60) = cos660

cos2x = cos660
2x = 660
x = 660/2
x = 330°

jadi
HP = {30°, 150°, 240°, 330°}

smg membantu