Description: Checking whether a given set of points can represent a function. For the set to represent a function, each domain element must have one corresponding range element at most. Created by Sal Khan and Monterey Institute for Technology and Education. Now, just as a refresher, a function is really just an association between members of a set that we call the domain and members of the set that we call a range. So if I take any member of the domain, let's call that x, and I give it to the function, the function should tell me what member of my range is associated with it. So this right over here not a function, because it's not clear if you input x what member of the range you're going to get.*Teacher Advisor is 100% free.