The intersection of two sets X and Y is the set of elements that are common to both set Xand set Y. It is denoted by X ∩ Y and is read ‘X intersection Y’.
Example:
Draw a Venn diagram to represent the relationship between the sets
X = {1, 2, 5, 6, 7, 9, 10} and Y = {1, 3, 4, 5, 6, 8, 10}
Solution:
We find that X ∩ Y = {1, 5, 6, 10} ← in both X and Y
For the Venn diagram,
Step 1 : Draw two overlapping circles to represent the two sets.
Step 2 : Write down the elements in the intersection.
Step 3 : Write down the remaining elements in the respective sets.
Notice that you start filling the Venn diagram from the elements in the intersection first.
If X ⊂Y then X ∩Y = X . We will illustrate this relationship in the following example.
Example:
Draw a Venn diagram to represent the relationship between the sets
X = {1, 6, 9} and Y = {1, 3, 5, 6, 8, 9}
Solution:
We find that X ∩ Y = {1, 6, 9} which is equal to the set X
For the Venn diagram,
Step 1 : Draw one circle within another circle
Step 2 : Write down the elements in the inner circle.
Step 3 : Write down the remaining elements in the outer circle.
Videos
Sets, Intersections, and Unions -
Professor Edward Burger explains sets, intersections, and unions.