For example, for any one-stepĬhange in x, is the change in y always going to be 3? Is it always going to be 5? If it's always going to be the

Tell them is for any given change in x, is the change Linear or non-linear? So linear functions, the way to but then the video wouldn't be making Sal's point which is how you can know that a function is linear just by looking at the table and this one is definitely not linear.įunction that contains the following points. Y = x² + 10, or if it showed the curve of a parabola with those points on it, then we would know that all the points were included. If the problem said that the function was defined by We haven't been told if x = 0 is included or x = 1/2 or x = -3Īnyway, those points in the table do lie on a parabola-we just don't know if there are any points between those. Sal only said that the function contains those points and no one tells us that there are any other points in the function. Technically, though, we don't know if this function is continuous or if it is defined by that table and only has those 5 points. A quadratic describes the points that make a parabola. So, in each case shown in the table, y = x² + 10 and that is definitely a quadratic. In Sal's table, notice that every value of y equals 10 plus x^2

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