Graphing a Function by Plotting Points. To find points of a function, we can choose input values, evaluate the function at these input values, and calculate output values. The input values and corresponding output values form coordinate pairs. We then plot the coordinate pairs on a grid.

Can points on a graph be a function?

A graph (or set of points) in the plane is a FUNCTION if no vertical line contains more than one of its points.

How do you tell if a plotted graph is a function?

Vertical Line Test

A set of points in the plane is the graph of a function if and only if no vertical line intersects the graph in more than one point.