General Procedure for Finding the Domain of a Function: The domain of a function consists of the values of such that is defined. These values can be determined by the function itself as well as the context of the function. Specifically, if involves any division, we cannot include in the domain of any value of that leads to division by zero. Similarly, if involves any square roots, we cannot include in the domain of any value of that leads to the square root of a negative number. If there is a context to , then we must also restrict its domain to consist of values of that make sense in that context. For example, demand functions only make sense when the quantity demanded, , is at least zero. Now consider the domain of . Note that there are two possible restrictions on the domain of based on the fact that the function involves division and square roots. Division: Since involves division, we have to make sure that we never divide by zero. In particular, we cannot include values of such that . This happens when (i.e., ). These are values of that cannot be included in the domain. Square Root