Answer:
cos(x-30)=1/2
Step-by-step explanation:
We use the following relationship to obtain cos(x)
From that, we have that cos(x)= sqrt(1-1/4)=sqrt(3) / 4
To obtain the value of cos(x-30), lets remember the following expression:
Therefor, we can use that to obtain our desired function cos(x-30)
cos(x)*cos(30)+sin(x)*sin(30)
=2/4=1/2