Answer:
The domain is all real numbers or [tex]x\in(-\infty,\infty)[/tex]
Step-by-step explanation:
The definition of domain is :
Domain is the set of x values for which the function is defined.
The given function is y = cos θ and we know that θ can take any value. In other words, for any value of θ, the function y = cos θ is defined.
Therefore, we can conclude that the domain of y = cos θ is the set of all real values.
In interval notation we can write it as
[tex]x\in(-\infty,\infty)[/tex]
