Arithmetic and Geometric Sequence Thursday, October 10, 2024 2:52 PM ARITHMETIC SEQUENCE An arithmetic sequence is a list of numbers with a definite pattern. If you take any number in the sequence then subtract it by the previous one, and the result is always the same or constant then it is an arithmetic sequence. Example 1 , 5 , 9 , 13, 17, 21, 25 . . l2 Page 1 MATHEMATICAL LANGUAGE AND SYMBOLS Thursday, October 10, 2024 3:03 PM The language of mathematics is the system used by mathematicians to communicate mathematical ideas among themselves. This language consists of a substrate of some natural language (ex. English) using technical terms and grammatical conventions peculiar to mathematical discourse, supplemented by a specialized symbolic notation for mathematical formulas. CHARACTERISTICS OF MATHEMATICAL LANGUAGE: PRECISE, CONCISE AND POWERFUL The language of mathematics makes it easy to express the kinds of symbols, syntax and rules that mathematicians like to do and is characterized by the following: ➢ Precise (able to make very fine distinctions) Example. The use of mathematical symbols is only done based on their meaning and purpose. Like “+” means add, “-” means subtract, “x” multiply and “÷” means divide. ➢ Concise (able to say things briefly) Example. The long English sentence can be shortened using mathematical symbols. Eight plus two equals ten which means 8 + 2 = 10. ➢ Powerful (able to express complex thoughts with relative ease) Example. The application of critical thinking and problem-solving skill requires the comprehension, analysis and reasoning to obtain the correct solution l3 Page 2 WRITING MATHEMATICAL LANGUAGE AS AN EXPRESSION OR SENTENCE ❖ an expression or mathematical expression is a finite combination of symbols that is well formed according to rules that depend on the context. It is a correct arrangement of mathematical symbols used to represent a mathematical object of interest. An expression does not state a complete thought; it does not make sense to ask if an expression is true or false. ❖ The most common expression types are numbers, sets, and functions. Numbers have lots of different names: for example, the expressions: 5 2+3 10/2 (6-2)+1 1+1+1+1 ❖ The basic syntax for entering mathematical formulas or expressions in the system enables you to quickly enter expressions using 2-D notation. The most common mistake is to forget the parentheses “( )”. For example, the expression: 1/(x+1) is different from 1/x+1 MATHEMATICAL LANGUAGE AND SYMBOLS .2 Thursday, October 10, 2024 3:03 PM The language of mathematics is the system used by mathematicians to communicate mathematical ideas among themselves. This language consists of a substrate of some natural language (ex. English) using technical terms and grammatical conventions peculiar to mathematical discourse, supplemented by a specialized symbolic notation for mathematical formulas. CHARACTERISTICS OF MATHEMATICAL LANGUAGE: PRECISE, CONCISE AND POWERFUL The language of mathematics makes it easy to express the kinds of symbols, syntax and rules that mathematicians like to do and is characterized by the following: ➢ Precise (able to make very fine distinctions) Example. The use of mathematical symbols is only done based on their meaning and purpose. Like “+” means add, “-” means subtract, “x” multiply and “÷” means divide. ➢ Concise (able to say things briefly) Example. The long English sentence can be shortened using mathematical symbols. Eight plus two equals ten which means 8 + 2 = 10. ➢ Powerful (able to express complex thoughts with relative ease) Example. The application of critical thinking and problem-solving skill requires the comprehension, analysis and reasoning to obtain the correct solution l3 Page 3 WRITING MATHEMATICAL LANGUAGE AS AN EXPRESSION OR SENTENCE ❖ an expression or mathematical expression is a finite combination of symbols that is well formed according to rules that depend on the context. It is a correct arrangement of mathematical symbols used to represent a mathematical object of interest. An expression does not state a complete thought; it does not make sense to ask if an expression is true or false. ❖ The most common expression types are numbers, sets, and functions. Numbers have lots of different names: for example, the expressions: 5 2+3 10/2 (6-2)+1 1+1+1+1 ❖ The basic syntax for entering mathematical formulas or expressions in the system enables you to quickly enter expressions using 2-D notation. The most common mistake is to forget the parentheses “( )”. For example, the expression: 1/(x+1) is different from 1/x+1 Four Basic Concepts of Mathematics 4 Sunday, October 27, 2024 1:09 PM 1.SET □ A set is a collection of welldefined objects that contains no duplicates. The objects in the set are called the “elements” of the set. To describe a set, we use braces [ ] and capital letters to represent it. The following are examples of sets: The books on the shelves in a library The bank accounts in the bank The set of natural numbers, N = {..., -3, -2, -1, 0, 1, 2, 3, ...} The integer numbers Z= {...,-3, -2, -1, 0, 1, 2, 3,...} The rational are numbers is the quotients of integers Q={p/q : p, q ∈ Z and q=0} The three dots enumerating the set’s elements are called ellipses and indicate a continuous pattern. A “finite set” contains elements that can be counted and terminates at a certain natural number, otherwise, it is an “infinite set”. Example: Set A = { 2, 4, 6, 8, 10} There is exactly one set, the empty set, or null set, ∅, or { }, which has no members at all. A set with only one member is called a singleton or a singleton set. “singleton of a” Specification of Sets There are three main ways to specify a set: List Notation/Roster Method by listing all its members – list names of elements of a set, separate them by commas, and enclose them in braces: Examples: 1. {1, 12, 45} 2. {George Washington, Bill Clinton} 3. {a, b, d, m} 4. “Three-dot abbreviation” {1, 2, . . . 1000} Predicate Notation/Rule Method/ SetBuilder Notation – by stating a property of its elements. It has a property that the members of the set share (a condition or a predicate that holds for members of this set). Examples: {y: y > 0} is read as: “the sets of all y’s such that y is greater than 0”. The set of all even numbers less than or equal to 10. The order in which the elements are listed is not relevant: i.e., the set {2, 4, 6, 8, 10} is the same as the set {8, 4, 2, 10, 6}. l4 Page 4 Four Basic Concepts of Mathematics 4.2 Sunday, October 27, 2024 Universal Sets – a set that contains all the elements considered in a particular situation and denoted by U. 1:09 PM Recursive Rules – by defining a set of rules which generates or define its members Examples: 1. The set E of even numbers greater than 3. a. 4 ∈ E b. If x ∈ E, then x + 2 ∈ E c. Nothing else belongs to E. Examples: • Suppose we list the digits only. Then, U = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} • Suppose we consider the whole numbers. Then, U = {0, 1, 2, 3, . . .} Subsets – a set is A 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 Example: Subsets 1. A = {7, 9} is a subset of B = {7, 8, 9} 2. D = {8, 9, 10} is subset of G = {10, 9, 8} Equal Sets Two sets are equal if contain the same elements. Examples: 1. { 3, 8, 9} = {8, 3, 9} 2. {6, 7, 7, 7, 7} = {6, 7} 3. {1, 3, 5, 7} ≠ {3, 5} A proper subset is a subset that is not equal to the original set, otherwise, it is an improper subset. A subset which contains all the elements of the original set. Example: Given {3, 5, 7} then the proper subsets are { }, {5, 7}, {3, 5}, {3, 7}. Equivalent Sets Two sets are equivalent if they contain the same number of elements. Examples: Which of the following sets are equivalent? {ö, ù, ø}, {£, €, ¥}, {1, 2, 3}, {a, b, c} Solution: All of the given sets are equivalent. The improper subset is {3, 5, 7} The Cardinality of the Set is the number of distinct elements belonging to a finite set. It is called the cardinal number of the set A denoted by n(A) or card (A) and |A|. For example, the cardinality of the set A = {1, 2, 3, 4, 5, 6} is equal to 6 because set A has six elements. The cardinality of a set is also known as the size of the set. l4 Page 5 Four Basic Concepts of Mathematics 4.3 Sunday, October 27, 2024 1:09 PM Operation of Sets Union is an operation for sets A and B in which a set is formed that consists of all the elements included in A or B or both denoted by u as A u B. Example: Given: U = {1, 2, 3, 4, 5, 6, 7, 8, 9}, A = {1, 3, 5, 7}, B ={2, 4, 6, 8} and C={1, 2}, find the following: a. A u B b. A u C c. (A u B) u {8} Intersection is the set containing all elements common to both A and B, denoted by ∩. Example: Given U = {a, b, c, d, e} , A={c, d, e}, B={a,b,c, e} and C = {a} and D = {e}. Find the following intersections of sets; a. B ∩ C b. A ∩ C c. (A ∩ B) ∩ D l4 Page 6 Complementation is an operation on a set that must be performed about a universal set, denoted by A’. Example. Give U = {a, b, c, d, e}, A={c, d, e}, Find A’. Functions and Relations Wednesday, October 30, 2024 9:44 PM CARTESIAN PRODUCTS OF SETS If set A and set B are two sets then the cartesian product of set A and set B is a set of all ordered pairs (a,b), such that a is an element of A and b is an element of B. It is denoted by A × B. Example: A = {1, 2} B = {x, y} The cartesian product A x B is. A x B = { (1,x) , (1,y), (2,x), (2,y) } ORDERED PAIRS An ordered pair, as its name suggests, is a pair of elements that have specific importance for the order of their placements. Ordered pairs are usually used in coordinate geometry to represent a point on a coordinate plane. Also, they are used to represent elements of a relation. RELATION A concept that defines the connection between elements of two sets. A relation is any set of ordered pairs. The set of all x-components of ordered pairs is called the domain of the relation and the set of all y-components is called range. Example: A = {1, 2} B= {1, 2, 3} A x B = {(1,1), (1,2), (1,3), (2,1), (2,2), (2,3) FUNCTIONS • A function is a special type of relation that assigns each element in one set, called the domain, to exactly one element in another set, called the codomain or range. • It is frequently desirable to work with a large class of functions rather than with a specific one, particularly in the development of the theory. Therefore, we use a symbol such as f(x), which is read “f of x”. To denote a function of x We write, = ( ) l5 Page 7 Functions and Relations .2 Wednesday, October 30, 2024 9:44 PM Types of Functions Based on Mapping Onto Function In an onto function, every codomain element is related to the domain element. In an onto function, no One-to-One Function element of codomain is left without A one-to-one function is defined by f: A → B such that every set A element is being mapped. For a function defined by f: A → B, such that every element connected to a distinct element in set B. The one-to-one function is also called in set B has a pre-image in set A. The onto function is also called a subjective an injective function. Here every element of the domain has a distinct function. image or co-domain element for the given function. Many-to-One Function A many-to-one function is defined by the function f: A → B, such that more than one element of the set A is connected to the same element in the set B. In a many-to-one function, more than one element has the same image. In a many-to-one function, if there is only a single value in the codomain that is mapped with all the elements of the domain, then it becomes a constant function. l5 Page 8 Into Function Into function is exactly opposite in properties to an onto function. Here certain elements in the co-domain do not have any pre-image. The elements in set B are excess and are not connected to any elements in set A. Functions and Relations .3 Wednesday, October 30, 2024 9:44 PM One One and Onto Function A function that is both a one and a onto function is called a bijective function. Here every element of the domain is connected to a distinct element in the codomain and every element of the codomain has a pre-image. Also, in other words every element of set A is connected to a distinct element in set B, and there is not a single element in set B that has been left out. Vertical Line Test A vertical line test is helpful to find if the given equation represents a function or not. The vertical line test states that a vertical line needs to cut the graph of a function(equation) at only one point to represent a function. If the graph of the equation represented in the coordinate axis, is cut by the vertical line at more than one point, then the graph is not a function. v An algebraic function is helpful in defining the various operations of algebra. The algebraic function has a variable, coefficient, constant term, and various arithmetic operators such as addition, subtraction, multiplication, and division. Algebraic Function The algebraic function can also be represented graphically. The algebraic function is again classified into the following functions based on their degree: • Linear functions • Quadratic functions • Cubic function • Polynomial functions l5 Page 9 Functions and Relations .4 Wednesday, October 30, 2024 9:44 PM Trigonometric Function The six basic trigonometric functions are f(θ) = sin θ, f(θ) = cos θ, f(θ) = tan θ, f(θ) = sec θ, f(θ) = cosec θ. Here the domain value θ is the angle and is in degrees or in radians. These trigonometric functions have been taken based on the ratio of the sides of a right-angle triangle, and are based on the Pythagoras theorem. Inverse Trigonometric Function The six basic inverse trigonometric functions are = sin−1( ), = cos−1 , =tan−1 , = csc−1 , =sec−1 , =cot−1( ). T he domain of the inverse trigonometric function contains real number values and its range has angles. The trigonometric functions and the inverse trigonometric functions are also sometimes referred to as periodic functions since the principal values are repeated Logarithmic and Exponential Functions Logarithmic functions have been derived from the exponential functions. The logarithmic functions are considered as the inverse of exponential functions. Logarithmic functions have a 'log' in the function and it has a base. The logarithmic function is of the form = log . l5 Page 10 v Modulus Function The modulus function gives the absolute value of the function, irrespective of the sign of the input domain value. The modulus function is represented as f(x) = |x|. The input value of 'x' can be a positive or a negative expression. The graph of a modulus function lies in the first and the second quadrants since the coordinates of the points on the graph are of the form (x, y), (-x, y). Rational Function A function that is composed of two functions and expressed in the form of a fraction is rational. A rational fraction is of the form f(x)/g(x), and g(x) ≠ 0. The graphical representation of these rational functions involves horizontal/vertical asymptotes, and the function does not touch the asymptotes. Functions and Relations .5 Wednesday, October 30, 2024 9:44 PM Signum Function The signum function helps us to know the sign of the function and does not give the numeric value or any other values for the range. The range of the signum function is limited to {-1, 0, 1}. For the positive value of the domain, the signum function answers 1, for negative values the signum function answers -1, and for the 0 value of a domain, the image is 0. The signum function has wide applications in software programming. Composite Function The composite functions are of the form of , ,( )( ) and are made from the individual functions of f(x), g(x), h(x). The composite functions made of two functions have the range of one function forming the domain for another function. Let us consider a composite function fog(x), which is made up of two functions f(x) and g(x). l5 Page 11 Inverse Function The inverse of a function f(x) is denoted by f-1(x). For the inverse of a function the domain and range of the given function are changed as the range and domain of the inverse function. The inverse of a function can be prominently seen in algebraic functions and in inverse trigonometric functions.