A.Definitin of set
set is collection of items or objects which can clearly described.Each member of the set is called element of the set.
We usually denote set with capital letters.
Examples:
1. Given A is the set of cities in central java.The elements of A are Purwokerto,Semarang,Kebumen,Solo,etc
2. B is the set of integers greater than-3.The elements of B are-2,-1,0,1,2,3,…
B.Notation of set
We write sets in brace or curly brackets ({ }).the writting of continuous set is done by writing ellipsis (‘…’) to indicate the elements which can’t be listed one by one. The membership of an element is symbolized in”Є” notation. If some objects don’t belong to a certain set we symbolize using”є”notation.
Suppose A is a set, then the number that symbolize the number of elements of A is called cardinal number. The number of elements of A or cardinal number of A is denote with n(A).
For example,given A={1,2,3,4,5,6}, then the number of elememts of A or n(A)=6.in set A we have 1є A, 2є A, 3є A, 4є A, 5ЄA, and 6є A.
C.Expressing a set
A set can be expressed in 3 ways. Those ways. Those ways are the following.
1.description
This is way in expressing a set in words of its membership property.
Exsamples:
*A={the name of city beginning with B}
