##
**SETS**

- Any collection of well-defined objects.

**TYPES OF SETS**

**1. Roster method or list method**

- this is the representation by listing down the elements of
the set.

- a set that has an element listed and is separated by a
comma.

**ILLUSTRATION:**

Set A = { a,e,i,o,u}

Set B = { 1,2,3,4,5,6 }

Set C = { 1,2,3,4….}

Set D = { nurse, doctor,patient}

Set D = { nurse, doctor,patient}

**2. Rule Method**

- a set where the members are described.

- this is a set that is representing its element by a
statement.

**ILLUSTRATION:**

Set A = { x/x is a set of vowel in an English Alphabet} [

*this means Set A = { a,e,i,o,u}*]
Set B = { x/x is a counting numbers less than 7} [

*this means Set B = { 1,2,3,4,5,6}*]
Set C = { x/x is a set of counting numbers} [

*this means Set C = { 1,2,3…..}*]**Exercises:**

**Let U = { x / x is a counting number less than 10}**

A

_{1 }= {1, 2, 4, 6, 8}
A

_{2 }= {2, 4, 5, 9}
A

_{3}= {x/x is a positive integer and x^{2}≤ 16}
A

_{4 }= {7, 8}**Compute:**

1.
A

_{1}U A_{2}
2.
A

_{1}U A_{2 }U A_{3 }
3. A

_{1 }∩ A_{2}∩ A_{3 }
4. A

_{1}∩ (A_{2}U A_{3})
5. (A

_{1}U A_{2})**’**

6. A

_{1 }U (A_{2 }∩ A_{3})
7. A'

_{3 }U_{ }A_{1 }_{}

_{8. }A

_{2}∩ A

_{3 }

_{}

_{9. }A

_{4 }∩ (A

_{2}U A

_{3})'

10. (A

_{4}U A_{1})_{ }∩ (A_{2}U A_{3})