Fundamentals of Mathematics (MATH 1510) Instructor: Lili Shen Email:
[email protected] Department of Mathematics and Statistics York University September 11, 2015 About the course Name: Fundamentals of Mathematics, MATH 1510, Section A. Time and location: Monday 12:30-13:30 CB 121, Wednesday and Friday 12:30-13:30 LSB 106. Please check Moodle regularly for course information, announcements and lecture notes: http://moodle.yorku.ca/moodle/course/view. php?id=55333 Be sure to read Outline of the Course carefully. Textbook James Stewart, Lothar Redlin, Saleem Watson. Precalculus: Mathematics for Calculus, 7th Edition. Cengage Learning, 2015. Towards real numbers In mathematics, a set is a collection of distinct objects. We write a 2 A to denote that a is an element of a set A. An empty set is a set with no objects, denoted by ?. Starting from the empty set ?, we will construct the set N of natural numbers: 0; 1; 2; 3; 4;::: , the set Z of integers: :::; −4; −3; −2; −1; 0; 1; 2; 3; 4;::: , the set Q rational numbers: all numbers that can be m expressed as the quotient of integers m; n, where n 6= 0, n and finally, the set R of real numbers. Natural numbers Natural numbers are defined recursively as: Definition (Natural numbers) 0 = ?, n + 1 = n [ fng. Natural numbers In details, natural numbers are constructed as follows: 0 = ?, 1 = 0 [ f0g = f0g = f?g, 2 = 1 [ f1g = f0; 1g = f?; f?gg, 3 = 2 [ f2g = f0; 1; 2g = f?; f?g; f?; f?ggg, :::::: n + 1 = n [ fng = f0; 1; 2;:::; ng, :::::: Integers and rational numbers Four basic operations in arithmetic: + − × ÷ Natural numbers Subtraction − Integers Division ÷ Rational numbers Integers and rational numbers Theorem Integers are closed with respect to addition, subtraction and multiplication.