lOMoARcPSD|16426846 Chapter 2. Mathematical Language AND Symbols Word Processing With Document Production (Cavite State University) StuDocu is not sponsored or endorsed by any college or university Downloaded by Aliah Mae Soriano (owensoriano21@gmail.com) lOMoARcPSD|16426846 Chapter 2 Mathematical Language and Symbols Language – the system of words, signs and symbols which people use to express ideas, thoughts and feelings. Mathematical Language – the system used to communicate mathematical ideas. A. Characteristic of Mathematical Language According to Jamison (2000) the use of language in mathematics differs from the language of ordinary speech in three important ways. First, mathematical language is non-temporal. Second, mathematical language is devoid of emotional content Third, mathematical language is precise. B. Mathematical Expression and Sentences Math can be words, expressions and sentences that can help students explain what they think. But before we tackle the Mathematical expression and Sentences , let try to translate the mathematics word to expression. 1. 2. 3. 4. 5. 6. The sum of twice a number and six. 2x + 6 The sum of a number and 9. X + 9 The difference of a number and twenty-one. X – 21 The product of six and a number. 6a or 6 x a The product of two and the sum of three and four. 2(3+4) Four is added to the product of eight and a number. 8a + 4 Mathematical Expression - Consist of term - Separated with other term with either plus or minus. - A single term may contain an expression in parenthesis or other grouping symbols. - Mathematical expression may consist numerical coefficient, literal coefficient and constant. Mathematical Sentence - Combines two mathematical expression using a comparison operator These expressions either use numbers, variables or both. The comparison operator include equal, not equal, greater than, greater than or equal to, less than and less than or equal to. Examples of Equation. Example of Inequality 4x + 3 = 19 15x -5 < 3y 6y – 5 = 55 18 > 16.5 Downloaded by Aliah Mae Soriano (owensoriano21@gmail.com) lOMoARcPSD|16426846 Open Sentence - means that it uses variables, meaning that it is not known whether or not the mathematical sentence is true or false. Closed Sentence – that known to be either true or false. It can be a TRUE CLOSED SENTENCE and FALSE CLOSED SENTENCE. Example of open sentence: 2xy < 3y 18 w > 16.5 3 (m + n) = 100 8ab –c = 1 x +y = 5 Example of TRUE CLOSED SENTENCE: 2 ( x + y ) = 2x + 2y 25 = 5 8c – c = 7c Example of FALSE CLOSED SENTENCE; 9 is an even number 10 – 1 = 8 The square root of 4 is 1. C. Conventions in the Mathematical Language There are many symbols in mathematics and most are used as a precise form of shorthand. We need to be confident when using these symbols, and to gain that confidence we need to understand their meaning. To understand their meaning there are two things to help us – D. 1. 2. 3. 4. CONTEXT - this is the context in which we are working, or the particular topics being studied, CONVENTION - where mathematicians and scientists have decided that particular symbols will have particular meaning. FOUR BASIC CONCEPTS SETS FUNCTIONS RELATIONS BINARY OPERATIONS 1. SETS – a well-defined collection of distinct object and is denoted by an uppercase letter Downloaded by Aliah Mae Soriano (owensoriano21@gmail.com) lOMoARcPSD|16426846 An object that belongs to a set is called an ELEMENT or MEMBER and it is usually denoted by lower case letter. The symbol “” denotes a membership while “” denotes non- membership to a set. Example X A read as x is an element of A. 1.1 Ways of Describing a Set ROSTER/ TABULAR METHOD - Method in which the elements in the given set are listed or enumerated, separated by a comma, inside a pair or braces. RULE/ DESCRIPTIVE METHOD - Method in which the common characteristics of the elements are defined. This method uses set builder notation where x is used to represent any element of the given set. Example. a. The distinct letters in the words “mathematics” Let A be the set of distinct etters of the word “mathematics” Roster form : A = {m, a, t, h, e, m, a, t, I, c, s} Rule form : A = {x∣x is the distinct letters in the words “mathematics” } b. The colors of the rainbow Let B be the set of the colors of the rainbow Roster form : A = {red, orange, yellow, green, blue , indgo, violet } Rule form : A = {x∣x is the colors of the rainbow } c. An even prime number Let C be the set of the even prime number Roster form : A = { 2 } Rule form : A = {x∣x is the even prime number} 1.2 KIND OF SET EMPTY/ NULL/ VOID SET – set that has no elements, denoted by Ø or by a pair of braces with no element inside. Ex. The set of numbers in the English Alphabet FINITE SET - a set with a countable number of elements. Ex. The set of letters in the English Alphabet INFINITE SET – a set has uncountable number of element Ex. The set of counting numbers UNIVERSAL SET - the totality of all the elements of the sets under consideration, denoted by U. Ex. The set of real numbers. 1.3 RELATIONSHIPS OF SETS Downloaded by Aliah Mae Soriano (owensoriano21@gmail.com) lOMoARcPSD|16426846 EQUAL SETS – set with same elements EQUIVALENT SETS – set with the same number of elements. Example: Let A = { x∣x is the distinct letter of the word “ read”} And Let B = { x∣x is the distinct letter of the word “ dear”} Therefore , sets A and B are equal sets, denoted by A = B since both sets have the elements a, d, e, and r. Since they have both four elements they are also consider as equivalent sets. Remember: It can be noted that equal sets are equivalent sets, however not all equivalent sets are equal sets. JOINT SETS - sets with at least one common element Example : Let E = { x∣x is the set of positive factors of 4 } and Let F = { x∣x is the set of positive factors of 9 } Since E = {1, 2, 4} and F = {1, 3, 9} wherein element 1 can be found both sets E and F, then these sets are said to be joint sets. DISJOINT SETS – set have no common element Example : Let E = { x∣x is the set of even numbers } and Let F = { x∣x is the set of odd number } SUBSET – set wherein every element of which can be found on the second set. ⊂ If the first set equals the second set, then it is an improper subset. The symbol ⊆ is used to mean improper subset. A null set is always a subset of any given set is considered an improper subset of the given set. Other than the set itself and the null set, are all considered proper subsets. The set containing all the subsets of the given set with n number of elements is called the power sets with number of elements. Example. Let T = { x∣x is the first three letters in English alphabet } = { a, b, c, } Since set T has three elements, then the power set has = 8 elements. Let S = { {a}, {b}, {c}, {a,b}, {a,c}, {b,c}, T, Ø } 1.4 OPERATIONS ON SETS Downloaded by Aliah Mae Soriano (owensoriano21@gmail.com) lOMoARcPSD|16426846 1. UNION OF SETS A and B (denoted by A U B ) - set whose elements are found in A or B or in both. Example. Let A = {a, b, c, d} B = { c, d, e } Then A U B = {a, b, c, d, e} 2. INTERSECTION of sets A and B (denoted by A ∩ B ) – set whose elements are common to both sets. Example. Let A = {a, b, c, d} B = { c, d, e } Then A ∩ B = { c, d} 3. DIFFERENCE of sets A and B (denoted by A - B ) – set whose elements are found in set A but not in set B. Example. Let A = {a, b, c, d} B = { c, d, e } Then A - B = { a, b } 4. COMPLIMENT OF Set A (denoted by A’) – the set of elements found in the universal set but not in set A. Example. Let U = {a, b. c, d, e} A = {a, b, c, d} B = { c, d, e } Then A’ = { e } B’ = { a, b } 1.5 Venn – Eular Diagrams or simply Venn Diagrams - Pictorial Presentation of Relationship and Operation of Sets - Universal Set is usually represented by a rectangle - While circles within the rectangle usually represent its subset - Shaded region in the given diagrams illustrates the sets relation or operation. 2. FUNCTION Downloaded by Aliah Mae Soriano (owensoriano21@gmail.com) lOMoARcPSD|16426846 A relation in which input has only one output Mathematical entities that give unique outputs to particular input A function (F) form a set of elements X to a set of elements Y is a rule that assigns to each element in x in X, exactly one element in y in Y. For Example: Let set X consists of four students and Set Y consists of their favorite subjects, respectively X = { Alyssa, Elijah, Steph, Shei } Y = { Chemistry, Math, Physics, Statistics } Then the result is a set of ordered pairs of the form (x, y), written as: {(Alyssa, Chemistry), (Elijah, Math), (Steph, Physics),( Shei, Statistics) } 3. RELATIONS - A set of inputs and outputs often expressed as ordered pairs. A relation can be represented as a o mapping diagram ( mapping or pairing from domain to the range is one way to show correspondence in a relation) graph relation ( Cartesian plane) To determine whether the given ordered pairs is function or not. We will used the VERTICAL LINE TEST (if all vertical lines intersect th o Downloaded by Aliah Mae Soriano (owensoriano21@gmail.com)