SparkNotes

U -cn F e, II Ov u, s cn '\- . A rclolion is a set of ordered pairs of values (c, gr) that "go together." Plotted on the Cartesian plane, a relation is any set of points- Ex: The unit circle in the plane is a relation; it is the set of points (r,gr) that satisfy 12 +'y2 :1. . A funclion is a set of ordered pairs (2, 9) so that for each z-value, there is no more thm one g-value. Plotted on the Cartesian plane, a function must pass the verlicol line fest: Every vertical line cuts the graph of the function at most once. Afunction cm be thought of as a role for generating val- ues. Plug in a value for the independent vodoble (fre- quently z) and receive a value for the dependenl vori- oble (frequently g). We say that "g is a function of r," md mite 9 : f @)-"9 eqtals f of r".