Post on 06-Aug-2015
transcript
TIF 21101
APPLIED MATH 1
(MATEMATIKA TERAPAN 1)
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
Week 3
SET THEORY
(Continued)
SET THEORYSET THEORY
OBJECTIVES:
1. Subset and superset relation
2. Cardinality & Power of Set
3. Algebra Law of Sets
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
3. Algebra Law of Sets
4. Inclusion
5. Cartesian Product
SET THEORYSET THEORY
Subset & superset relationWe use the symbols of:
⊆ � is a subset of
⊇ � is a superset of
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
We also use these symbols⊂ � is a proper subset of
⊃ � is a proper superset of
Why they are different?
SET THEORYSET THEORY
They maen……
S⊆T means that every element of S is also an element of T.
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
an element of T.
S⊇T means T⊆S.
S⊂T means that S⊆T but .
SET THEORYSET THEORY
Examples:
• A = {x | x is a positive integer ≤ 8}
set A contains: 1, 2, 3, 4, 5, 6, 7, 8
• B = {x | x is a positive even integer < 10}
set B contains: 2, 4, 6, 8
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
set B contains: 2, 4, 6, 8
• C = {2, 6, 8, 4}
• Subset Relationships
A ⊆ A A ⊄ B A ⊄ C
B ⊂ A B ⊆ B B ⊂ C
C ⊄ A C ⊄ B C ⊆ C
Prove them !!!
SET THEORYSET THEORY
Cardinality and The Power of Sets
|S|, (read “the cardinality of S”), is a measure of
how many different elements S has.
E.g., |∅|=0, |{1,2,3}| = 3, |{a,b}| = 2,
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
E.g., |∅|=0, |{1,2,3}| = 3, |{a,b}| = 2,
|{{1,2,3},{4,5}}| = ……
P(S); (read “the power set of a set S”) , is the set
of all subsets that can be created from given set S.
E.g. P({a,b}) = {∅, {a}, {b}, {a,b}}.
SET THEORYSET THEORY
Example:
A = {a, b, c} where |A| = 3
P (A) = {{a, b}, {a, c}, {b, c}, {a}, {b}, {c}, A, φ}
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
P (A) = {{a, b}, {a, c}, {b, c}, {a}, {b}, {c}, A, φ}and |P (A)| = 8
In general, if |A| = n, then |P (A) | = 2n
How about if the set of S is not finite ? So we say S infinite.
Ex. B = {x | x is a point on a line}, can you difine them??
SET THEORYSET THEORY
Langkah-langkah menggambar diagram venn
1. Daftarlah setiap anggota dari masing-masing himpunan
2. Tentukan mana anggota himpunan yang dimiliki secara bersama-sama
3. Letakkan anggota himpunan yang dimiliki bersama ditengah-tengah
4. Buatlah lingkaran sebanyak himpunan yang ada yang melingkupi
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
4. Buatlah lingkaran sebanyak himpunan yang ada yang melingkupi anggota bersama tadi
5. Lingkaran yang dibuat tadi ditandai dengan nama-nama himpunan
6. Selanjutnya lengkapilah anggota himpunan yang tertulis didalam lingkaran sesuai dengan daftar anggota himpunan itu
7. Buatlah segiempat yang memuat lingkaran-lingkaran itu, dimana segiempat ini menyatakan himpunan semestanya dan lengkapilah anggotanya apabila belum lengkap
SET THEORYSET THEORY
Diketahui : S = { x | 10 < x ≤ 20, x ∈ B }
M = { x | x > 15, x ∈ S }
N = { x | x > 12, x ∈ S }
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
N = { x | x > 12, x ∈ S }Gambarlah diagram vennya
SET THEORYSET THEORY
Jawab : S = { x | 10 < x ≤ 20, x ∈ B } = { 11,12,13,14,15,16,17,18,19,20 }
M = { x | x > 15, x ∈ S } = { 16,17,18,19,20}
N = { x | x > 12, x ∈ S } = { 13,14,15,16,17,18,19,20}
M ∩∩∩∩ N = { 16,17,18,19,20 }
Diagram Vennya adalah sbb:
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
16
17
18
1920
MN
13
14 15
S
11
12
Diagram Vennya adalah sbb:
SET THEORYSET THEORY
Set’s Inclusion and Exclusion
For A and B, Let A and B be any finite sets. Then :
A ∪ B = A + B – A ∩ B
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
In other words, to find the number n(A ∪ B) of elements in the union A ∪ B, we add n(A) and n(B) and then we subtract n(A ∩ B); that is, we “include” n(A) and n(B), and we “exclude” n(A ∩ B). This follows from the fact that, when we add n(A) and n(B), we have counted the elements of A ∩ B twice. This principle holds for any number of sets.
Inclusion Exclusion
SET THEORYSET THEORY
Set’s Inclusion and Exclusion
For A and B, Let A and B be any finite sets. Then :
A ∪ B = A + B – A ∩ B
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
In other words, to find the number n(A ∪ B) of elements in the union A ∪ B, we add n(A) and n(B) and then we subtract n(A ∩ B); that is, we “include” n(A) and n(B), and we “exclude” n(A ∩ B). This follows from the fact that, when we add n(A) and n(B), we have counted the elements of A ∩ B twice. This principle holds for any number of sets.
Inclusion Exclusion
SET THEORYSET THEORY
Inclusion and Exclusion of Sets
For A and B, Let A and B be any finite sets. Then :
A ∪ B = A + B – A ∩ B
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
In other words, to find the number n(A ∪ B) of elements in the union A ∪ B, we add n(A) and n(B) and then we subtract n(A ∩ B); that is, we “include” n(A) and n(B), and we “exclude” n(A ∩ B). This follows from the fact that, when we add n(A) and n(B), we have counted the elements of A ∩ B twice. This principle holds for any number of sets.
Inclusion Exclusion
Inclusion-Exclusion Principle
• How many elements are in A∪B?|A∪B| = |A| + |B| − |A∩B|
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
• Example:
{2,3,5}∪{3,5,7} = {2,3,5,3,5,7} ={2,3,5,7}
Contoh:
Dari 60 siswa terdapat 20 orang suka bakso, 46 orang suka siomay dan 5 orang tidak suka keduanya.a. Ada berapa orang siswa yang suka bakso dan siomay?
b. Ada berapa orang siswa yang hanya suka bakso?
c. Ada berapa orang siswa yang hanya suka siomay?
Jawab: N(S) = 60
Misalnya : A = {siswa suka bakso} n(A) = 20
B = {siswa suka siomay} n(B) = 46
(A ∩∩∩∩B)c = {tidak suka keduanya} n((A ∩∩∩∩B)c) = 5
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
Maka A ∩∩∩∩B = {suka keduanya}
(A ∩∩∩∩B)c = {tidak suka keduanya} n((A ∩∩∩∩B)c) = 5
n(A ∩∩∩∩B) = x
{siswa suka bakso saja} = 20 - x
{siswa suka siomay saja} = 46 - x
Perhatikan Diagram Venn berikut
xA B20 - x 46 - x
S
5
n(S) = (20 – x)+x+(46-x)+5
60 = 71 - x
X = 71 – 60 = 11a. Yang suka keduanya adalah x
= 11 orangb. Yang suka bakso saja adalah
20-x = 20-11= 9 orang
c. Yang suka siomay saja adalah
46-x = 46-11= 35 orang
SET THEORYSET THEORY
Berapa banyaknya bilangan bulat antara 1
dan 100 yang habis dibagi 3 atau 5?
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
Cartesian Products of Sets
• For sets A, B, their Cartesian product
A×B :≡ {(a, b) | a∈A ∧ b∈B }.
• E.g. {a,b}×{1,2} = {(a,1),(a,2),(b,1),(b,2)}
• Note that for finite A, B, |A×B|=|A||B|.
Matematika Terapan 12014/2015 M. Ilyas Hadikusuma, M.Eng
• Note that for finite A, B, |A×B|=|A||B|.
• Note that the Cartesian product is not
commutative: A×B ≠ B×A.