Answer:
Domain: -∞ < x < ∞
Range: -1 ≤ y ≤ 1
Option A is correct
Step-by-step explanation:
The given function is:
y = cos x
The graph of y = cos x is plotted below
The domain of a function is a set of all the valid/real inputs of that function
The range of a function is a set of all the valid/real outpouts
Note that the given cosine function (y = cos x) can take in all real values of x. This means that is domain is a set of all real numbers
cosx has a range between -1 and 1
Therefore, the domain and range of y = cos x are:
Domain: -∞ < x < ∞
Range: -1 ≤ y ≤ 1