Answer:
A function [tex]f[/tex] from a set [tex]A[/tex] to a set [tex]B[/tex] is a relation that assigns to each element [tex]x[/tex] in the set [tex]A[/tex] exactly one element [tex]y[/tex] in the set [tex]B[/tex]. The set [tex]A[/tex] is the domain (also called the set of inputs) of the function and the set [tex]B[/tex] contains the range (also called the set of outputs).
- First figure is not a function because the x-coordinate 2 has more than one element in the set of outputs.
- Second figure is a function because this each element [tex]x[/tex] in the set [tex]A[/tex] is assigned to exactly one element [tex]y[/tex] in the set [tex]B[/tex].
- Third figure is not a function because the x-coordinates -1, 1 and 2 have assigned more than one element in the set of outputs.
- Fourth figure is a function because this each element [tex]x[/tex] in the set [tex]A[/tex] is assigned to exactly one element [tex]y[/tex] in the set [tex]B[/tex].
