Chapter 2 Flashcards
Set
A collection of objects whose contents can be clearly determined.
Ex. Sofa set, tea set, a deck of cards
*capital letters are usually used to name sets
Elements/members
Objects within a set(parts that make up the whole)
Well defined set
Sets where the contents can be clearly determined
Ex. The number of states in the USA
Not well defined sets
Sets where the elements are not clear and/or up for debate
Ex. The best cars
Order of elements (members)
The way each element is displayed within a set. The order is not important
Ex. P={1, 2, 3} and P= {2, 3, 1} are both valid ways to show a set
Methods to represent a set
- Description
- Roster Method
- Set building rotation/Scientific form
All can show the same set but in different forms
The sets can be transformed from on to another without losing its meaning
Word description method
Describes the members in a set
Ex. Set W is a set of days in a week
Roster form method
Includes braces and uses commas to separate elements
Ex. A={1,2,3,4}
Set builder notation method
The name of set is a term such that the term is whatever elements create the set
Ex. W: {x|x is the set of days of the week}
Empty sets
Sets with no members
Represented by:
{ }
Ø
Purpose of ellipses
Ellipses can be used to continue members within a longer set
Ex. L= {a,b,c,…x,y,z}
Being though Set L is the set of letters in the alphabet…which has 26 letters
Notation of membership
Shows which members are apart of a set
Symbols:
€ or /€
Natural numbers
Numbers used when counting (not including 0)
Set of natural numbers
Sets with members which are natural numbers
N={1,2,3…}
Equivalent Set
Sets with the same amount of members; sets can be equal and equivalent but not all equivalent sets are equal
n(A)=n(B)
One to one correspondent
Ex. A={2,3,4,5} is equivalent with B={9,10,11,12}
