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).
The graph of a function [tex]f[/tex] is the collection of ordered pairs [tex](x,f(x))[/tex] such that [tex]x[/tex] is in the domain of [tex]f[/tex] being:
[tex]x[/tex] the directed distance from the [tex]y-axis[/tex].
[tex]y=f(x)[/tex] the directed distance from the [tex]x-axis[/tex].
By plotting the function [tex]f(x)=-(x+1)^2[/tex] we get the graph illustrated below.
From this graph, we know that:
