cos x = sin 75° , 0

Sinx = Cos (90°-x)
Sin 75° = Cos (90°-75°)
Sin 75° = Cos 15°

jawab

cos x = sin 75
cos x = cos (90 -75)
cos x = cos 15
x = 15 + k. 360  atau x  = -15 + k. 360
k = 0 , x = 15 , x = -15
k = 1 , x = 375 , x = 345
interval   0 ≤ x ≤ 360
x = {15, 345 }