Hello!
A cubic function is in the form of .
All cubic functions have a domain of all real numbers, the range also has a range of all real numbers.
Interval notation is used for representing a function/interval as a pair of numbers. Parentheses and brackets are used to show if the endpoints of a given function/interval are included or excluded. Brackets allow the endpoints to be included while parentheses exclude the endpoint.
Our first instinct would be that the domain is written as [-∞, ∞], but that is incorrect. Infinity is not a number, but it is a concept. This means that they are excluded from the domain.
Therefore, the domain of the function f(x) is (-∞, ∞).