MATHEMATICAL LANGUAGE AND SYMBOLS CHAPTER 2 THE LANGUAGE, SYMBOLS, SYNTAX AND RULES OF MATHEMATICS The language of mathematics is the systematic used by mathematicians to communicate mathematical ideas among themselves. Mathematics as a language has symbols to express a formula or to represent a constant. It has syntax to make the expression well-formed to make the characters and symbols clear and valid thar do not violate the rules. Symbol Meaning Example + Add 3+7 = 10 - Subtract 10-3 = 7 x Multiply 5x6 = 30 ÷ Divide 45 ÷5 = 9 / Divide 45/5 = 9 π Pi 𝐴 = 𝜋𝑟 2 ∞ Infinity ∞ is endless = Equal 1+1 = 2 ≈ Approximately π ≈ 3.14 ≠ Not equal to 3≠4 <≤ Less than, less than or equal to 2<3 >≥ Greater than, greater than or equal to 5>2 √ Square root √4 = 2 ° Degrees 20° Therefore A=B B=A PERFORM OPERATIONS ON MATHEMATICAL EXPRESSION CORRECTLY P Parenthesis E Exponents M Multiplication D Division A Add S Subtraction 11 − 5 6 2 2 ×2−3+1 ×2−3+1 16 − 3 8 − 3 16 − 3 5 2 2 ÷5 36 × 2 − 3 + 1 16 − 3(25) ÷ 5 72 − 3 + 1 16 − 75 ÷ 5 73 − 3 16 − 15 70 1 ÷5 THE FOUR BASIC CONCEPTS OF MATHEMATICS Set A set is a collection of well-defined objects that contains no duplicates. The objects in the set are called elements of the sets. To describe a set, we use braces {} and use capital letters to represent it. Z = {1, 2, 3, …} Relation A relation is a rule that pairs each elements in one set, called the domain, with one or more elements from a second set called range. It create sets of ordered pairs. Holidays Month and Date New Year’s Day January 1 Labor Day May 1 Independence Day June 12 Bonifacio Day November 30 Rizal Day December 30 SPECIFICATIONS OF SET There are three main ways to specify a set: 1. List Notation/ Roster Method – by listing all its members Examples: 1. {1, 12, 24} 2. {a, b, d, m} 2. Predicate Notation / Rule Method – by stating a property od its elements. Examples: 1. {x|x is a natural number and x<8} than 8” means “the set of all x such that x is a natural number and is less 2. {y|y is a student of UC-Banilad and y is older than 25} 3. Recursive Rules – by defining a set of rules which generates or define its members. Examples: 1. the set of E of even numbers greater than 3: a. 4∈ E b. if x ∈ E, then x+2 ∈ E c. nothings else belongs to E EQUAL SETS Two sets are equal if they contain exactly the same elements Examples: 1. {3, 8, 9} = {9, 8, 3} 2. {6, 7, 7, 7, 7} = {6, 7} 3. {1, 3, 5 , 7} ≠ {3, 5} EQUIVALENT SETS Two sets are equivalent if they contain the same number of elements. Examples: {1, 2, 3} , {a, b, c} , ∞, 𝜃, 1 , { , , } All of the given sets are equivalent. ***Note that no two of then are equal but they all have the same number of elements. UNIVERSAL SET A set that contains al elements considered in a particular situation and denoted by 𝑼. Examples: a. Suppose we list the digits only. Then 𝑼 = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} b. Suppose we consider the whole numbers Then 𝑼 = {0, 1, 2, 3, 4, ….} since 𝑼 contains all numbers SUBSETS A set A is called a subset of set B if every element of A is also an element of B. “ A is a subset of B is written as A⊆ 𝐁. Examples: 1. A = {7, 9} is a subset of B = {6, 9, 7} 2. D = {10, 8, 6} is a subset of G = {10, 8, 6} A⊆B D⊆G PROPER SUBSET AND IMPROPER SUBSET Proper subset is a subset that is not equal to the original set, otherwise improper subset. Examples: Given: {3, 5, 7} Proper subset: {}, {5, 7} , {3, 5} , {3,7} Improper subset : {3, 5, 7} CARDINALITY OF THE SET It is the number of distinct elements belongings to a finite set. It is also called the cardinal number of the set A denoted by 𝑛 A or card A and |A|. OPERATIONS OF SETS Union – is an operation of set A and B in which a set is formed that consists of all the elements included A or B both denoted by ∪ as A ∪ B. Examples: 𝑼 = {1, 2, 3, 4, 5, 6, 7, 8, 9} A ={ 1, 3, 5, 7} B = {2, 4, 6, 8} C= {1, 2} Find the following: a. A ∪ B b. A ∪ C c. (A ∪ B) ∪ {8} Solution: a. A ∪ B = {1, 2, 3, 4, 5, 6, 7, 8} b. A ∪ C = {1, 2, 3, 5, 7} c. (B ∪ C) = {1, 2, 4, 6, 8} OPERATIONS OF SETS Intersection – It is the set containing all elements common to both A and D denoted by ∩. Examples: 𝑼 = {a, b, c, d, e} A ={ c, d, e} B = {a, c, e} C = {a} D = {e} Find the following: a. B ∩ C b. A ∩ C c. (A ∩ B) ∩ D Solution: a. B ∩ C = {a} b. A ∩ C = ∅ c. (A ∩ B) ∩ D = {c, e} ∩ {e} = {e} OPERATIONS OF SETS Complementation – is an operation on a set that must be performed in reference to a universal set denoted by 𝑨′ . Examples: 𝑼 = {a, b, c, d, e} A ={ c, d, e} B = {a, c, e} Find the following: a. 𝐴′ b. 𝐵′ Solution: a. 𝐴′ = {a, b} b. 𝐵′ = {b, d} THE FOUR BASIC CONCEPTS OF MATHEMATICS Functions It is a rule that pairs each elements in one set, called domain (X) and range (Y). This means that for each first coordinate, there is exactly one second coordinate or for every first elements of X, there corresponds a unique second element Y Binary A binary operation on a set is a calculation involving two elements of the set to produce another element of the set. A new math (binary) operation, using the symbol *, is defined to be a*b = 3a+b, where a and b are real numbers. Examples: What is 4*3? 4*3 = 3(4) +3 a= 4 b=3 12+ 3 15 ELEMENTARY LOGIC According to David W. Kueker, logic is simply defined as the analysis of methods of reasoning. Mathematical Logic is the study of reasoning as used in mathematics. In ordinary mathematical English the use of “therefore” customarily indicates that the following statements is a consequence of what comes before. Examples: 1. All men are mortal. Luke is a man. Hence, Luke is mortal. 2. All dogs like fish. Cyber is a dog. Hence, Cyber likes fish. LOGICAL OPERATORS / CONNECTIVES Proposition (statement) is a sentence that is either true or false (without additional information) denoted by P and Q The logical connectives are defined by truth tables. Connectives Symbol Words Negation ~ or ¬P Not / The opposite Conjunction p^q And / Both are True Disjunction pvq Or / One is true, then all is True Implication p Bi-conditional p q If, then / False if q is false and p is true/ True if q is true and p is false q If and only if / True when p and q are both true or false. TRUTH TABLE p q ¬p Negation ¬q p^q pvq p q Negation Conjunction Disjunction Implication p q Biconditional T T F F T T T T T F F T F T F F F T T F F T T F F F T T F F T T p q ¬p ¬p v q (¬p v q) ^ p q ¬p (¬p v q) T T F T T F F T F F F F T F F T T T F T F F F T T F T F (q ¬p)