The range of a function is the set of all possible output values generated by the function for a given domain. It is a measure of how the output values of a function are distributed and can be used to analyze the behavior of the function and its applications in various contexts.
For example, consider the function with a domain of all real numbers. The range of this function is all non-negative real numbers because the output of the function will always be greater than or equal to $0$ for any input value of .
The domain of a function is the set of all possible input values for which the function is defined.