Question

Tolong dijawab
Nilai fungsi diatas dapat sebesar?

Answer 1

Ubah bentuk 4 cos x - 2√5 sin x + 9 = k cos (x - α) + 9
a = 4
b = -2√5
k = √(a²+b²) = 6
4 cos x - 2√5 sin x + 9 = 6 cos (x - α) + 9

nilai  maksimum cos (x- a ) = 1 --> y = 15/ (6 +9) = 1
nilai minimum cos(x-a) = -1 --->  y = 15/(-6+9) = 5