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 IIC, 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.
