Applied Math Lesson 2.1 ­ complete.notebook
LESSON 2.1
BASIC SET CONCEPTS
SET: A set is a collection of objects whose contents can be clearly determined. August 28, 2015
The Empty Set
­Also called the Null Set
­ Represented by { } or ­ The set that contains no elements
METHODS FOR REPRESENTING A SET:
1. Use a capital letter
Examples: {States that start with z}
"W" for the days of the week
"N" for the set of Natural Numbers {1,2,3,4...}
{x| x<4 and x>10}
2. A word description
"the set of the days of the week"
3. Roster method: a list inside a pair of brackets { }
{Monday, Tuesday, Wednesday...} 4. Set ­ Builder Notation: {x| x is the set of...}
Empty set? Yes or No? Explain.
{x| x<3 or x>15 }
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Aug 28­1:26 PM
True or False. Explain.
5 N
7 { 1, 2, 3... 50}
2.7 N
m {a, b, c... z}
What do you think means?
x What do you think means?
H { A, B, C, X, Y, Z }
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Cardinal Number
­ The number of elements in a set.
­Represented by n(A) for set A.
­ Two sets are equal iff they have exactly the same elements, regardless of order and repetition. {4,8,9} = {9,4,8,4}
Examples: find n(A) if...
2. A = {13, 14, 15 ... 22, 23}
Finite Set ­ A set is finite (ending) if it's number of elements is countable, including the empty set with n(A) = 0.
3. A = { 0 }
A = {1, 2, 3... 100}
4. A = B = {1, 2, 3...}
1. A = {7, 9, 11, 13}
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Applied Math Lesson 2.1 ­ complete.notebook
August 28, 2015
Sep 2­8:00 AM
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