Consider the function
This function is periodic with a period of 175.9
To avoid ambiguity, consider two functions as a second function:
The first one is a periodic function with a period of
How did we find it? Simplify the sum of a sine and cosine of the same argument, you get
This is a simple sine function that is certainly periodic. The period of a periodic function is
The function 2.2 is not a periodic function.