what is a domain in math

In math, the domain of a function is the set of values that can be plugged into the function. It is the set of input values for which the function is defined. The range, on the other hand, is the set of output values that the function can produce. The domain is important to know because some functions have limits on what is permissible as an input. For example, a function cannot have a denominator of zero, so the domain of a function with a fraction in it cannot include the value that would make the denominator zero. The domain can be written in interval notation or set notation. If the domain is not explicitly stated, it is typically assumed to be the largest subset of real numbers where the function could be defined.