Sets
Already in this chapter we’ve covered how to analyze the
data in a set and how to deal with two sets that have overlapping
members. For the Math IC, there are two more concepts concerning
sets that you need to understand: union and intersection.
Union
The
union of two or more sets is the set
that contains all of the elements of the two original sets. The
union of two sets
A and
B is symbolized
this way:
For example, the union of the sets A =
{1, 2, 3, 4, 5} and B = {4, 5, 6,
7, 8} is
This set contains every element that is in either set.
If
x is an element of
then it must be an element of
A, or
of
B, or of both.
Intersection
The
intersection of two sets is the set of
their overlapping elements. The intersection of the two sets
A and
B is
symbolized as
The intersection of the sets
A = {1,
2, 3, 4, 5} and
B = {4, 5, 6, 7, 8}, for example,
is
= {4,5}. If
x is
an element of
then
x must
be an element of both
A and B.
