fungsi f(x) = 4sin (pi/3 + x) maksimum untuk x =....

maksimum jika
sin(phi/3 + x) = 1
sin(phi/3 + x) = sin90
phi/3 + x = 90
x = 90 - phi/3
x = 90 - 60
x = 30°

atau
x = 1/6 phi