what is the domain of (f(x)=cos(x))?\no the set of real numbers (-2pileq xleq2pi)\no the set of real numbers…

Answer:

D. the set of all real numbers

Explanation:

Step1: Recall cosine function property

The cosine function $y = \cos(x)$ is defined for any real - valued input $x$.

Step2: Analyze domain concept

The domain of a function is the set of all possible input values. Since we can substitute any real number for $x$ into $y=\cos(x)$ and get a well - defined output (a value between - 1 and 1), the domain is the set of all real numbers.