Answer:
Frequency =

Explanation:
We are given the following function and we are to find its frequency:

We know that the standard form of cosine function is

where
is the amplitude,
while
is the mid line.
Frequency is given by:
where
is frequency and
is the period.
Finding period by comparing the given function:


Substituting B to get:


So, Period = 2.
Since frequency is
, therefore
Frequency =
