We have to find the frequency of given function f(x)=1/4 cos(2x)+5 for this we will adopt the general procedure of first finding the period and then use the general relation frequency=1/period and find the frequency.
In the given function f(x)=1/4 cos(2x)+5 only the constant 2 which will multiply with x effects the period
As we know that 2π is the period of cosx then the period of cos(2x) is
2x=2π
x=π
So, the period of cos(2x) is π
Now the frequency is F=1/π
