# 1. Number of Elements in A 2. Inclusion-Exclusion Principle 3. Venn Diagram 4. De Morgan's Laws 1.

## Presentation on theme: "1. Number of Elements in A 2. Inclusion-Exclusion Principle 3. Venn Diagram 4. De Morgan's Laws 1."— Presentation transcript:

1. Number of Elements in A 2. Inclusion-Exclusion Principle 3. Venn Diagram 4. De Morgan's Laws 1

2 If S is any set, we will denote the number of elements in S by n(S). For example, if S = {1,7,11}, then n(S) = 3; if S =, then n(S) = 0.

3 Inclusion-Exclusion Principle Let S and T be sets. Then

 Let S = {presidents with an undergraduate degree in business} and T = {presidents with a graduate degree in business}.  S T = {presidents with degrees (of any sort) in business}  S T = {presidents with both undergraduate and graduate degrees in business} 5

 n ( S ) = 238  n ( T ) = 184  n ( S T ) = 310  n ( S T ) = n ( S ) + n ( T )  n ( S T )  310 = 238 + 184  n ( S T )  n ( S T ) = 238 + 184  310 = 112 6

 A Venn diagram is a drawing that represents sets geometrically. To construct a Venn diagram, draw a rectangle and view its points as the elements of U. Then draw a circle inside the rectangle for each set. The circles should overlap. View the points inside the circles as elements of each set. 7

 Draw a Venn diagram with three sets, R, S and T. Shade the area that represents R S T, R S T and S R ' T '. 8

9

10 De Morgan's Laws Let S and T be sets. Then (S T)' = S' T', (S T)' = S' T'.

11 Verify (S T)' = S ‘ T ' using Venn diagrams.

12

13

 The inclusion-exclusion principle says that the number of elements in the union of two sets is the sum of the number of elements in each set minus the number of elements in their intersection. 14

 A Venn diagram consists of a rectangle containing overlapping circles and is used to depict relationships among sets. The rectangle represents the universal set and the circles represent subsets of the universal set.  De Morgan's laws state that the complement of the union (intersection) of two sets is the intersection (union) of their complements. 15

Download ppt "1. Number of Elements in A 2. Inclusion-Exclusion Principle 3. Venn Diagram 4. De Morgan's Laws 1."

Similar presentations