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Saturday, February 29, 2020
TOP SCORERS FOR MIDTERM ( February 2020 )
TOP SCORERS FOR MIDTERM
Given on February 19 – 21, 2020
MW 101 – Math in the Modern World (200 students)
Name Score
1. Reighxyne Joules Viado 100
Jose Jerry Labrador 100
Queenie Rose Orong 100
Johana Dalamban 100
Nasria Talusob 100
2. Maria Nina Nicole Singco 98
3. Saharia Kusain 96
4. Ronnilyn Yambao 90
5. Novelyn Balbuena 88
6. Trisha Ramirez 87
7. Monalisa Talusob 86
8. Sittie Aisa Magao 85
Rohaina Laguiab 85
Christine Jane Ursua 85
Justine Ericka Bayog 85
Chennie Marianne Galleto 85
Daryl Hannah Buagas 85
Baby Jane Dumamba 85
Josel Esparagoza 85
Melody Cadangin 85
9. April Rose Del Rio 84
Angel Valerie Ledda 84
Jame Choella Pitulan 84
10. Joezeil Pagulong 81
Jenelyn Melocotones 81
Joeseph Caalim 81
Kenneth Andea 81
Reymark Calambro 81
Nicko Jay Andan 81
Honeylyn Zerrudo 81
11. Danica Mae Singco 80
Justine Ericka Bayog 85
Chennie Marianne Galleto 85
Daryl Hannah Buagas 85
Baby Jane Dumamba 85
Josel Esparagoza 85
Melody Cadangin 85
9. April Rose Del Rio 84
Angel Valerie Ledda 84
Jame Choella Pitulan 84
10. Joezeil Pagulong 81
Jenelyn Melocotones 81
Joeseph Caalim 81
Kenneth Andea 81
Reymark Calambro 81
Nicko Jay Andan 81
Honeylyn Zerrudo 81
11. Danica Mae Singco 80
MATH 106 – Logic and Set Theory ( 24 students )
Name Score
1. Sabila Mamalampay 98
2. Bailyn Tukuran 96
3. Danilo Derio Jr. 92
4. Marvin Chiva 89
5. Annie Rose Rosa 88
6. Joseph Gabe 87
7. Kenneth John Pernal 85
8. Ahmad Ulanan 83
4. Marvin Chiva 89
5. Annie Rose Rosa 88
6. Joseph Gabe 87
7. Kenneth John Pernal 85
8. Ahmad Ulanan 83
Tuesday, January 7, 2020
TOP SCORERS FOR TRINALS
TOP SCORERS FOR TRINALS
Given on December 17 – 18, 2019
MW 101 – Math in the Modern World
Name Score1. Trisha V. Ramirez 86
Ronnilyn C. Yambao 86
Mac Royce D. Diano 86
2. Reighxyne Joules Viado 84
Rohaina M. Laguiab 84
3. Roosevelt Ger Dojinog 82
4. Justine Ericka Bayog 81
5. Jose Jerry Labrador 80
MATH 106 – Mathematical Logic and Set Theory
Name Score1. Joseph B. Gabe 100
Danilo E. Derio Jr. 100
Benladin S. Samier 100
2. Dominic J. Martinez 99
3. Sabila M. Mamalampay 98
4. Datu Ali A. Pandaupan 97
Annie Rose D. Rosa 97
5. Jean P. Bautista 95
Ahmad G. Ulanan 95
Stephiene C. Pasagui 95
Kenneth John C. Pernal 95
6. Bhlyzyr Thryz R. Diaz 94
Joshua G. Larazan 94
Bailanie A. Sumlay 94
7. Kaye J. Bolina 91
8. Bailyn E. Tukuran 89
9. Jonna Fe J. Gorit 87
10. Vaneza Joy Y. Largo 86
11. John Lloyd C. Salvallon 85
12. Marvin C. Chiva 84
13. Shery Mae D. Angcon 82
Efren F. Cadungog, Sr. , MIM
Class Adviser
Wednesday, December 11, 2019
MW 101 LESSON 2
SPEAKING MATHEMATICALLY
2.1 Variables
Variable is sometimes thought of as a mathematical “John Doe” because you can use it as a placeholder when you want to talk about something; either
a) you imagine that it has one or more values but you don’t know what they are,
b) you want whatever you say about it to be equally true for all elements in a given set and you don’t want to be restricted to considering only a particular, concrete value for it.
Example of the first use of a variable:
Is there a number with the following property: doubling it and adding 3 gives the same result as squaring it?
In this statement, we introduce a variable to replace the potentially ambiguous word “it”
Is there a number x with the property that 2 x + 3 = x2 ?
The advantage of using a variable is that it allows you to give a temporary name to what you are seeking so that you can perform concrete computations with it to help discover its possible values. To emphasize the role of the variable as a placeholder, you might write the following:
Is there a number with the property that 2 × + 3 = 2 ?
The emptiness of the box can help you imagine filling it in with a variety of different values, some of which might make the two sides equal and others of which might not.
To illustrate the second use of variables, consider the statement:
No matter what number might be chosen, if it is greater than 2,
then its square is greater than 4.
In this case introducing a variable to give a temporary name to the (arbitrary) number you might choose enables you to maintain the generality of the statement, and replacing all instances of the word “it” by the name of the variable ensures that possible ambiguity is avoided:
No matter what number n might be chosen, if n is greater than 2, then n2 is greater than 4.
Example : Writing sentences using variables.
a. Are there numbers with the property that the sum of their squares equals the square of their sum.
b. Given any real number, its square is nonnegative.
Solution :
a) Are there numbers a and b with the property that a2 + b2 = ( a + b)2 ?
Or, Are there numbers a and b such that a2 + b2 = ( a + b)2 ?
Or, Do there exist any numbers a and b such that a2 + b2 = ( a + b)2 ?
b) Given any real number r, r2 is nonnegative.
Or, For any real number r, r2 ³ 0.
Or, For all real numbers r, r2 ³ 0.
Kinds of Mathematical Statements
1. Universal statements
2. Conditional statements
3. Existential statements
* A universal statement states that a certain property is true for all elements in a set.
Ex 1. All even numbers are multiples of 2.
Ex 2. All integers ending in 0 and 5 are divisible by 5.
* A conditional statement states that if one thing is true then some other thing also has to be true.
Ex 1. If 1296 is divisible by 12, then 1296 is divisible by 6.
Ex 2. If I am thirsty, then I will drink.
* An existential statement states that there is at least one thing for which the property is true.
Ex 1. There is an x in x2 – x – 6 = 0, such that a) x is odd, b) x is even.
Ex 2. There is a prime number that is even.
UNIVERSAL CONDITIONAL STATEMENTS
Universal statements contain some variation of the words, “For all”, and conditional statements contain versions of the words, “if-then”. A universal conditional statement is a statement that is both universal and conditional.
Ex. 1. For all animals A, if A is a dog, then A is a mammal.
A universal conditional statement can be written in ways that make them appear to be purely universal or purely conditional. The previous example can be transformed in a way that makes its conditional nature explicit but its universal nature implicit:
If A is a dog, then A is a mammal.
Or: If an animal is a dog, then the animal is a mammal.
The statement can also be expressed so as to make its universal nature explicit and its conditional nature implicit:
For all dogs A, A is a mammal.
Or : All dogs are mammals.
Rewriting a Universal Conditional Statement
Exercise 1. Fill in the blanks to rewrite the following statement.
For all real numbers x, if x is nonzero then x2 is positive.
a) If a real number is nonzero, then its square _____.
b) For all nonzero real number x, _____.
c) If x is ______, then ______.
d) The square of any nonzero real number is ______.
e) All nonzero real numbers have ______.
Answers:
a) is positive.
b) x2 is positive.
c) is a nonzero real number, x2 is positive.
d) positive.
e) positive squares( or squares that are positive).
UNIVERSAL EXISTENTIAL STATEMENTS
A universal existential statement is a statement that is universal because its first part says that a certain property is true for all objects of a given type, and it is existential because its second part asserts the existence of something.
Ex. Every real number has an additive inverse.
In this statement the property “has an additive inverse” applies universally to all real numbers. “Has an additive inverse” asserts the existence of something – an additive inverse – for each real numbers. The nature of the additive inverse depends on the real number, and the statement can be rewritten in several ways; some less formal and some more formal.
All real numbers have additive inverses.
Or: For all real numbers r, there is an additive inverse for r.
Or: For all real numbers r, there is a real number s such that s is an additive inverse for r.
Introducing names for the variables simplifies references further in discussion. For instance, after the third version of the statement, you may write :
When r is positive, s is negative, when r in negative, s is positive and when r is zero, s is also zero.
One of the most important reasons for using variables in mathematics is that it gives you the ability to refer to quantities unambiguously throughout a lengthy mathematical argument, while not restricting you to consider only specific values for them.
REWRITING UNIVERSAL EXISTENTIAL STATEMENT
Fill in the blanks to rewrite the following statement:
Every pot has a lid.
a) All pots ______.
b) For all pots P, there is a ______.
c) For all pots P, there is a lid L such that _______.
Answers:
a) have lids.
b) a lid for P.
c) L is a lid for P.
EXISTENTIAL UNIVERSAL STATEMENTS
An existential universal statement is a statement that is existential because its first part asserts that a certain object exists and is universal because its second part says that the object satisfies a certain property for all things of a certain kind. For example:
There is a positive integer that is less than or equal to every positive integer.
This statement is true because the number one is positive integer, and it satisfies the property of being less than or equal to every positive integer. The statement can be rewritten in several ways, some less formal and some more formal:
Some positive integer is less than or equal to every positive integer.
Or: There is a positive integer m that is less than or equal to every positive integer.
Or: There is a positive integer m such that every positive integer is greater than or equal to m.
Or: There is a positive integer m with the property that for all positive integers n, m £ n.
REWRITING AN EXISTENTIAL UNIVERSAL STATEMENT
Fill in the blanks to rewrite the following statement in three different ways:
There is a person in my class who is at least as old as every person in my class.
a) Some _____ is at least as old as _____.
b) There is a person P in my class such that P is _____.
c) There is a person P in my class with the property that for every person P in my class, p is ____.
Answers:
a) person in my class, every person in my class.
b) at least as old as every person in my class.
c) at least as old as q.
Some of the most important mathematical concepts, such as the definition of a limit of a sequence, can only be defined using phrases that are universal, existential and conditional, and they require the use of all three phrases “for all”, “there is”, and “if – then”.
Example:
If a1, a2, a3, . . . is a sequence of real numbers, saying that
the limits of an as n approaches infinity is L
means that
for all positive real numbers e, there is an integer N such that
for all integers n, if n > N then –e < an – L < e .
Exercise set 2.1
SETS
1.2 The Language of sets
Georg Cantor (1845 – 1918) introduced the word set as a formal mathematical term in 1879.
A SET is a well-defined collection of objects. The objects are the members of the elements of the set.
Examples of sets : Well-defined sets Not well-defined set
1. Set of solution to x2 – 7x + 6 = 0. 1. Set of presidents
2. Set of vowels of the English alphabet. 2. Set of subjects
3. Set of positive integers greater than 1 but less than 8 3. Set of municipalities
4. Set of cities of Region XII.
Notation:
Sets are denoted by capital letters, such as A, B, C, D, X, Y . . . whereas the lower case letters such as a, b, c, x, y . . . is used to denote members or elements of the set.
If S is a set, the notation x S, means that x is an element of S. The notation x S, means that x is not an element of S.
A set may be specified using a set-roster notation by writing all the elements between braces.
Examples :
If N is a set of countries of the UN, then the Philippines is an element of N.
If B is a set of positive even integers greater than 1 but less than 8, then 4 is an element of B.
If C is a set of cities of Region XII, then Koronadal City is an element of C.
Is Africa an element of N?
Is 5 an element of B?
Is Malaybalay City an element of C?,
A variation of the notation is used to describe a very large set, as when we write
{1, 2, 3, 4, . . . , 100}
to refer to a set of all integers from 1 to 100. A similar notation can also describe an infinite set, as when we write {1, 2, 3, . . . } to refer to a set of all integers.
The symbol . . . is called an ellipsis and is read “and so forth.”
An axiom of extension says that a set is completely determined by what its elements are – not the order in which they might be listed or the fact that some elements might be listed more than once.
Example 1 : Using the set-roster notation
a. Let A = {1, 2, 3}, B = {3, 1, 2}, and C = {1, 1, 2, 3, 3, 3}. What are the elements of A, B, and C? How are A, B, and C related ?
b. Is { 0 } = 0?
c. How many elements are in the set {1, { 1 } } ?
d. For each nonnegative integer n, let Un = { n, – n}. Find U1, U2 and U0.
Solution :
a. A, B, and C have exactly the same three elements: 1, 2, and 3. Therefore, A, B, and C are simply different ways to represent the same set.
b. {0} ¹ 0 because {0} is a set with one element, namely 0, whereas 0 is just the symbol that
represents the number zero.
c. The set {1, { 1 } } has two elements: 1 and the set whose only element is 1.
d. U1 = { 1, – 1}, U2 = { 2, – 2}, U0 = { 0, – 0} = { 0, 0} = { 0 }
Certain set of numbers are so frequently referred to that they are given special symbolic names. These are summarized in the table below.
The set of real numbers is pictured as the set of all points on a line as shown on the real number line. The number 0 corresponds to a middle point, called the origin. The set of real numbers is divided into three parts: the set of positive real numbers, the set of negative real numbers, and the number 0. Note that 0 is neither positive nor negative.
The real number line is continuous because it is imagined to have no holes. Every integer is a real number, and because the integers are all separated from each other, the set of integers is discrete.
SET–BUILDER NOTATION
Another way to specify a set uses a set-builder notation. Let S denote a set and let P(x) be a property that elements of S may or may not satisfy. We may define a new set to be the set of elements x in S such that P(x) is true. The set is denoted by
Occasionally we write { x | P(x) } without being specific about where the element x comes from.
2.1 Variables
Variable is sometimes thought of as a mathematical “John Doe” because you can use it as a placeholder when you want to talk about something; either
a) you imagine that it has one or more values but you don’t know what they are,
b) you want whatever you say about it to be equally true for all elements in a given set and you don’t want to be restricted to considering only a particular, concrete value for it.
Example of the first use of a variable:
Is there a number with the following property: doubling it and adding 3 gives the same result as squaring it?
In this statement, we introduce a variable to replace the potentially ambiguous word “it”
Is there a number x with the property that 2 x + 3 = x2 ?
The advantage of using a variable is that it allows you to give a temporary name to what you are seeking so that you can perform concrete computations with it to help discover its possible values. To emphasize the role of the variable as a placeholder, you might write the following:
Is there a number with the property that 2 × + 3 = 2 ?
The emptiness of the box can help you imagine filling it in with a variety of different values, some of which might make the two sides equal and others of which might not.
To illustrate the second use of variables, consider the statement:
No matter what number might be chosen, if it is greater than 2,
then its square is greater than 4.
In this case introducing a variable to give a temporary name to the (arbitrary) number you might choose enables you to maintain the generality of the statement, and replacing all instances of the word “it” by the name of the variable ensures that possible ambiguity is avoided:
No matter what number n might be chosen, if n is greater than 2, then n2 is greater than 4.
Example : Writing sentences using variables.
a. Are there numbers with the property that the sum of their squares equals the square of their sum.
b. Given any real number, its square is nonnegative.
Solution :
a) Are there numbers a and b with the property that a2 + b2 = ( a + b)2 ?
Or, Are there numbers a and b such that a2 + b2 = ( a + b)2 ?
Or, Do there exist any numbers a and b such that a2 + b2 = ( a + b)2 ?
b) Given any real number r, r2 is nonnegative.
Or, For any real number r, r2 ³ 0.
Or, For all real numbers r, r2 ³ 0.
Kinds of Mathematical Statements
1. Universal statements
2. Conditional statements
3. Existential statements
* A universal statement states that a certain property is true for all elements in a set.
Ex 1. All even numbers are multiples of 2.
Ex 2. All integers ending in 0 and 5 are divisible by 5.
* A conditional statement states that if one thing is true then some other thing also has to be true.
Ex 1. If 1296 is divisible by 12, then 1296 is divisible by 6.
Ex 2. If I am thirsty, then I will drink.
* An existential statement states that there is at least one thing for which the property is true.
Ex 1. There is an x in x2 – x – 6 = 0, such that a) x is odd, b) x is even.
Ex 2. There is a prime number that is even.
UNIVERSAL CONDITIONAL STATEMENTS
Universal statements contain some variation of the words, “For all”, and conditional statements contain versions of the words, “if-then”. A universal conditional statement is a statement that is both universal and conditional.
Ex. 1. For all animals A, if A is a dog, then A is a mammal.
A universal conditional statement can be written in ways that make them appear to be purely universal or purely conditional. The previous example can be transformed in a way that makes its conditional nature explicit but its universal nature implicit:
If A is a dog, then A is a mammal.
Or: If an animal is a dog, then the animal is a mammal.
The statement can also be expressed so as to make its universal nature explicit and its conditional nature implicit:
For all dogs A, A is a mammal.
Or : All dogs are mammals.
Rewriting a Universal Conditional Statement
Exercise 1. Fill in the blanks to rewrite the following statement.
For all real numbers x, if x is nonzero then x2 is positive.
a) If a real number is nonzero, then its square _____.
b) For all nonzero real number x, _____.
c) If x is ______, then ______.
d) The square of any nonzero real number is ______.
e) All nonzero real numbers have ______.
Answers:
a) is positive.
b) x2 is positive.
c) is a nonzero real number, x2 is positive.
d) positive.
e) positive squares( or squares that are positive).
UNIVERSAL EXISTENTIAL STATEMENTS
A universal existential statement is a statement that is universal because its first part says that a certain property is true for all objects of a given type, and it is existential because its second part asserts the existence of something.
Ex. Every real number has an additive inverse.
In this statement the property “has an additive inverse” applies universally to all real numbers. “Has an additive inverse” asserts the existence of something – an additive inverse – for each real numbers. The nature of the additive inverse depends on the real number, and the statement can be rewritten in several ways; some less formal and some more formal.
All real numbers have additive inverses.
Or: For all real numbers r, there is an additive inverse for r.
Or: For all real numbers r, there is a real number s such that s is an additive inverse for r.
Introducing names for the variables simplifies references further in discussion. For instance, after the third version of the statement, you may write :
When r is positive, s is negative, when r in negative, s is positive and when r is zero, s is also zero.
One of the most important reasons for using variables in mathematics is that it gives you the ability to refer to quantities unambiguously throughout a lengthy mathematical argument, while not restricting you to consider only specific values for them.
REWRITING UNIVERSAL EXISTENTIAL STATEMENT
Fill in the blanks to rewrite the following statement:
Every pot has a lid.
a) All pots ______.
b) For all pots P, there is a ______.
c) For all pots P, there is a lid L such that _______.
Answers:
a) have lids.
b) a lid for P.
c) L is a lid for P.
EXISTENTIAL UNIVERSAL STATEMENTS
An existential universal statement is a statement that is existential because its first part asserts that a certain object exists and is universal because its second part says that the object satisfies a certain property for all things of a certain kind. For example:
There is a positive integer that is less than or equal to every positive integer.
This statement is true because the number one is positive integer, and it satisfies the property of being less than or equal to every positive integer. The statement can be rewritten in several ways, some less formal and some more formal:
Some positive integer is less than or equal to every positive integer.
Or: There is a positive integer m that is less than or equal to every positive integer.
Or: There is a positive integer m such that every positive integer is greater than or equal to m.
Or: There is a positive integer m with the property that for all positive integers n, m £ n.
REWRITING AN EXISTENTIAL UNIVERSAL STATEMENT
Fill in the blanks to rewrite the following statement in three different ways:
There is a person in my class who is at least as old as every person in my class.
a) Some _____ is at least as old as _____.
b) There is a person P in my class such that P is _____.
c) There is a person P in my class with the property that for every person P in my class, p is ____.
Answers:
a) person in my class, every person in my class.
b) at least as old as every person in my class.
c) at least as old as q.
Some of the most important mathematical concepts, such as the definition of a limit of a sequence, can only be defined using phrases that are universal, existential and conditional, and they require the use of all three phrases “for all”, “there is”, and “if – then”.
Example:
If a1, a2, a3, . . . is a sequence of real numbers, saying that
the limits of an as n approaches infinity is L
means that
for all positive real numbers e, there is an integer N such that
for all integers n, if n > N then –e < an – L < e .
Exercise set 2.1
Fill
in the blanks to rewrite the given statements.
1. For
all objects O, if O is a square then O has four sides.
a.
All squares _____________ .
b.
Every square ____________ .
c.
If an object is a square, then it
__________ .
d.
If O _____ , then
O _________ .
e.
For all squares O, ____________ .
2. For
all equations E, if E is quadratic then E has at most two real solutions.
a.
All quadratic equations ____________ .
b.
Every quadratic equation ___________ .
c.
If an equation is quadratic, then it _________ .
d.
If E ________ , then E _______________
.
e.
For all quadratic equation E,
__________ .
3. Every
positive number has a positive square root.
a.
All positive numbers ______ .
b.
For any positive number N, there
is _______ for N.
c.
For all positive numbers N, there
is a positive number r such that ______ .
4. Every nonzero real number has a reciprocal.
a.
All nonzero real numbers ______ .
b.
For all nonzero real numbers r, there is ______ for r.
c.
For all nonzero real numbers r, there is a real number s such that
_____.
5.
There is a real number whose product with every number leaves the number
unchanged.
a.
Some ______ has the property that its ______ .
b.
There is a real number r such that the product of r
______.
c.
There is a real number r with the property that for every real number s,
______ .
Fill in the blanks using variable or variables to rewrite the given
statements.
1. Is there an integer tha has a
remainder of 2 when it is divided by 5 and a remainder of 3 when it is divided
by 6?
a) Is there an integer n such
that n has _______ ?
b) Does there exist ________
such that if n is divided by 5 the remainder is 2 and if ______ ?
c) Give at least one example of this
integer.
2. Given any two real numbers, there
is a real number in between.
a) Given any two real numbers x and y, there a real number r such
that r is ______ .
b) For any two ______ , _______ such that x <
r < y.
3. Is there a real number whose square
is – 1?
a) Is there a real number x such that _____ ?
b) Does there exist ______ such that x2 = – 1 ?
c) Give at least one example of this
number.
4. Given any real number, there is a
real number that is greater.
a) Given any real number r ,
there is _____ s such
that s
is ______ .
b) For any ______ , _______ such
that s > r.
5. The cube root of any negative real
number is negative.
a) Given any negative real number s , the cube root of ______ .
b) For any real number s , if
s is _____ , then _______ .
c) If a real number s
______, then ______ .
SETS
1.2 The Language of sets
Georg Cantor (1845 – 1918) introduced the word set as a formal mathematical term in 1879.
A SET is a well-defined collection of objects. The objects are the members of the elements of the set.
Examples of sets : Well-defined sets Not well-defined set
1. Set of solution to x2 – 7x + 6 = 0. 1. Set of presidents
2. Set of vowels of the English alphabet. 2. Set of subjects
3. Set of positive integers greater than 1 but less than 8 3. Set of municipalities
4. Set of cities of Region XII.
Notation:
Sets are denoted by capital letters, such as A, B, C, D, X, Y . . . whereas the lower case letters such as a, b, c, x, y . . . is used to denote members or elements of the set.
If S is a set, the notation x S, means that x is an element of S. The notation x S, means that x is not an element of S.
A set may be specified using a set-roster notation by writing all the elements between braces.
Examples :
If N is a set of countries of the UN, then the Philippines is an element of N.
If B is a set of positive even integers greater than 1 but less than 8, then 4 is an element of B.
If C is a set of cities of Region XII, then Koronadal City is an element of C.
Is Africa an element of N?
Is 5 an element of B?
Is Malaybalay City an element of C?,
A variation of the notation is used to describe a very large set, as when we write
{1, 2, 3, 4, . . . , 100}
to refer to a set of all integers from 1 to 100. A similar notation can also describe an infinite set, as when we write {1, 2, 3, . . . } to refer to a set of all integers.
The symbol . . . is called an ellipsis and is read “and so forth.”
An axiom of extension says that a set is completely determined by what its elements are – not the order in which they might be listed or the fact that some elements might be listed more than once.
Example 1 : Using the set-roster notation
a. Let A = {1, 2, 3}, B = {3, 1, 2}, and C = {1, 1, 2, 3, 3, 3}. What are the elements of A, B, and C? How are A, B, and C related ?
b. Is { 0 } = 0?
c. How many elements are in the set {1, { 1 } } ?
d. For each nonnegative integer n, let Un = { n, – n}. Find U1, U2 and U0.
Solution :
a. A, B, and C have exactly the same three elements: 1, 2, and 3. Therefore, A, B, and C are simply different ways to represent the same set.
b. {0} ¹ 0 because {0} is a set with one element, namely 0, whereas 0 is just the symbol that
represents the number zero.
c. The set {1, { 1 } } has two elements: 1 and the set whose only element is 1.
d. U1 = { 1, – 1}, U2 = { 2, – 2}, U0 = { 0, – 0} = { 0, 0} = { 0 }
SET–BUILDER NOTATION
Another way to specify a set uses a set-builder notation. Let S denote a set and let P(x) be a property that elements of S may or may not satisfy. We may define a new set to be the set of elements x in S such that P(x) is true. The set is denoted by
ORDERED PAIR
Given elements a and b, the symbol (a,
b) denotes the ordered pair consisting of a and b together with the specification
that a
is the first element of the pair and
b is the second element. Two ordered pairs (a, b) and (c, d) are equal
if, and only if a = c and b = d.
Symbolically:
(a, b) = (c, d) means that a = c and b = d.
CARTESIAN PRODUCT
Given sets A and B,
the Cartesian product of A and B, denoted by A x B
and read as “A cross B”, is the set of all ordered pairs (a, b), where a
is in A and b is in B. Symbolically:
A x B = { (a, b) | a Î A and b Î B }
Example 6: Cartesian product
Let A = { 1, 2, 3 } and B
= { m, p }
a.
Find A x B
b.
Find B x A
c.
B x B
d.
How many elements are in A x B, B x A and B x B?
e.
Let R denote the set of all real numbers.
Describe R x R.
Solution :
a.
A x B = { (1, m), (2, m), (3, m),
(1, p), (2, p), (3, p) }
b. B x A = { (m, 1), (m, 2), (m, 3), (p, 1), (p, 2), (p,
3) }
c. B x B = { (m, m), (m, p), (p, m), (p, p) }
d. A x B has six elements. This is the number of elements in A times the
number of elements in B.
B x A has six elements, the number of elements
in B times the number of elements in A.
B x B has four elements, the number
of elements in B times the number of elements in B.
e. R x R is the set of all
ordered pairs (x, y) where both x and y are real numbers. If horizontal and vertical axis are drawn on a plane
and a unit length is marked off, then each ordered pair in R x R corresponds to a unique point in
the plane, with the first and the second elements of the pair indicating the abscissa and
ordinate the point.
The term Cartesian plane is
often used to refer to a plane with this coordinate system, as shown in the figure:
1.3 The
Language of Relation and Function
There
are many kinds of relationships in the world. Two people are related by blood
if they share a common ancestor, we also have a relationship between student
and teacher, between people who work for
the same employer, and between people who have a common ethnic background.
The
objects of mathematics maybe related in many ways. A set B maybe related to a
set C if B is a subset of C, or B is not a subset of C, or B and C have a
common element. A number x is related to a number y if x < y, or if x is a factor of y,
or if x2 + y2 = 1.
Identifiers
in a computer program are related if they have the same first eight characters,
or the same memory location is used to
store their values when the program executes.
Let
A = {0, 1, 2} and B = {1, 2, 3 }. An element x in A is related to an element y
in B if, and only if, x is less than y.
The notation xRy is shorthand for
the sentence “x is related to y”. From the given set:
0 R 1
since 0 < 1
0 R 2
since 0 < 2
0 R 3
since 0 < 3
1 R 2
since 1 < 2
1 R 3 since
1 <
3 and
2 R 3
since 2 < 3
Thursday, November 14, 2019
Lesson 1 MATH 106 - Logic and Set Theory
LOGIC
It is not easy to summarize in a few
paragraphs the subject matter known as logic. For lawyers and judges, logic is
the science of correct reasoning. They use logic to communicate more
effectively, construct valid arguments, analyze legal contracts, and make
decisions. Law schools consider knowledge of logic to be one of the most
important predictors of future success of their new students. A sizable portion
of the LSAT (Law School Admission Test) considers logical reasoning as part of
their admission process.
Other professions also make extensive
use of logic. Programmers use logic to design computer software, electrical
engineers use logic to design circuits for smart phones, and mathematicians use
logic to solve problems and construct mathematical proofs. In this chapter, you
will encounter several facets of logic. Specifically, logic is use to
·
Analyze
information and the relationship between statements
·
Determine
the validity of arguments
·
Determine
valid conclusions based on given assumptions, and
·
Analyze
electronic circuits.
LOGIC
STATEMENTS AND QUANTIFIERS
Gottfried Wilhelm Leibniz (1646 – 1716) was one of the mathematicians
who make a serious study of symbolic logic. He tried to advance the study of
logic from a merely philosophical subject to a formal mathematical subject.
Leibniz never completely achieve his
goal; however several mathematicians such as Augustus De Morgan (1806 – 1871)
and George Boole (1815 – 1864), contributed to the advancement of symbolic
logic as a mathematical discipline.
Boole published “The Mathematical
Analysis of Logic” in 1848. In 1854 he published the more extensive work, “An Investigation of the Laws of Thought”.
With these documents, the mathematician Bertrand Russell stated, “Pure
mathematics was discovered by Boole in a work which is called The Laws of Thought.”
LOGIC
STATEMENT
Statement or Proposition is a declarative
sentence that is either true or false, but not both true and false. It is
typically expressed as a declarative sentence (as opposed to question or
command). Propositions are the basic building blocks of any theory of logic.
Every language contains different types of
sentences, questions, and commands. For instance,
“Is there a rain today?” is a question.
“Go and set that bird free” is a
command.
“This is a nice design” is an
opinion.
“Pasig City is the capital of the
province of Rizal” is a statement of fact.
The symbolic logic that Boole was
instrumental in creating applies only to declarative sentences.
Examples.
Determine whether each sentence is
statement.
1. Mexico is in Africa.
2. How are your parents ?
3. 99 + 2 is a prime number.
4. x + 2 = 4
Answers:
1. Statement with a truth value
of false because Mexico in Central America.
2. It’s a question and not a
declarative sentence, hence not
statement.
3. You may not know that 99
+ 2 is a prime number, however, you know
that it is a whole number larger than 1, so it is either a prime number or it
is not a prime number. The sentence is either true or false, and it is not both
true and false, so it is a statement.
4. x + 2 =
4 is a statement, known as an
open statement and is true only for x = 2, and false for any other values of x.
Exercises:
Which
of the following are statements or proposition ?
1.
The only positive integer that divide 5 are 1 and 5 itself.
2.
2 + 4 = 7
3. The
earth is an oblate spheroid.
4.
4 – x = 7.
5.
Do you speak Chinese?
6. Oh,
what a beautiful site!
7.
Buy three tickets for the concert on November 25, 2018.
8.
The only positive integer that divide 12 are 3, 4 and itself.
9.
A square is a rectangle having all sides equal.
10. A
circle is round.
SIMPLE STATEMENTS AND COMPOUND STATEMENTS
A simple statement is a statement that
conveys a single idea. A compound statement is
statement that conveys two or more ideas. Connecting simple statements with
words and phrases such as and, or,
not, if...then, and if and only if
creates a compound statement. For
instance, “I will go to school and I will join the debate” is a compound. It is
composed of two simple statements “I will go to school” and “I will join the
debate.” The word and is the
connective for the two simple statements.
George
Boole used the letters p, q, r,
and s
to represent simple statements and the symbols Ù, Ú, ~, ® and « to represent connectives.
Let
us define the meaning of these connectives by showing the relationship between
the truth value (i.e. true or false) of composite propositions and those of
their component propositions.
Let
p and q be propositions.
a) The conjunction of p and q, denoted by p L q, is the proposition p and q.
b) The disjunction of p and q, denoted by p
V q, is the proposition p or q.
c) The negation of p, denoted by ~p, is the proposition not p.
Propositions such as p L q and p V q that result from
combining propositions are called compound propositions. The compound statement
p L
q is true when both p and q are true; otherwise, it is false. The compound
statement p V q is true if at least one
of p or q is true, it is false when both p and q are false.
The
truth value of a simple statement is either true ( T) or false ( F). The truth
value of a compound statement depends on the truth values of its simple statements
and its connectives. The truth values of
propositions such as conjunctions and disjunctions can be described by truth
tables. The truth table shows the truth value of compound statement for all
possible truth values of its simple statements.
The truth table of a proposition
p made up of the individual propositions p1...pn, lists
all possible combinations of truth values for p1...pn ,T
denoting true and F denoting false and for each such combination lists the
truth value of p.
NEGATION
Write
the negation of each statement.
1.
p: Today is not Friday.
~p: Today is Friday.
2.
p: The seventh month is July.
~p: The seventh month is not July.
3. p: Mathematical logic is not an easy
subject.
4.
p: Tacurong City is a city in the
province of Sultan Kudarat.
5.
p: The national flower is
sampaguita.
6.
p: Tarsiers are abundant in the
province of Bohol.
7.
p: Vatican City is a city within
a City.
8.
p: Japan is the land of the
rising sun.
9.
p: Cagayan de Oro City is known
as the City of Golden Friendship.
10. p: Cebu
City is the Queen City of the South.
CONJUNCTION, Ù and DISJUNCTION, Ú
Given p:
Today is Monday.
q:
The weather is cold.
r:
I passed the test.
s: I will be very happy.
1. p Ù q : Today is Monday and the weather is cold.
2. r Ù s : I passed the test and I will be very happy.
3. p Ú q : Today is Monday or the weather is cold.
4. r Ú s :
5. ~p Ù q :
6. r Ù ~s :
7. p Ú ~q :
8. ~r Ú s :
9. q Ú s
10.
p Ù r
11.
q Ú ~s
12.
~p Ù r
Consider the following simple
propositions.
p:
Today is Tuesday.
q: It is a sunny day.
r: I am going to the gym.
s: I am not going to play
basketball.
Write the following compound statements
in symbolic form.
1. Today is Tuesday and it is a
sunny day.
2. It is not a sunny day and I am
going to the gym.
3. I am going to play basketball
or I am not going to the gym.
4. It is not a sunny day and
today is not Tuesday.
5. I am not going to play
basketball or I am not going to the gym.
6. I am going to play basketball
and I am going to the gym.
7. It is not a sunny day and
today is Tuesday.
8. I am going to play basketball
and today is Tuesday.
Answers :
1. p Ù q
2. ~q Ù r
Consider
the following statements
p:
The game will be played in New York.
q:
The game will be shown on ABC 5.
r:
The game will not be shown on ABS-CBN.
s:
The GSW are favored to win.
Write
each of the following symbolic statements in words.
1. p Ù q 6. ~p Ù ~q
2. q Ù p 7. q Ù ~p
3. p Ú ~r 8. ~p Ú ~r
4. q Ù s 9. s Ù q
5. q Ú ~ r 10.
~q Ú r
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