이산수학 7판 솔루션 (DISCRETE MATHEMATICS 7판 솔루션 ) Johnsonbaugh

Johnsonbaugh-50623

book

November 19, 2007

14:54

HINTS/SOLUTIONS TO

Selected Exercises

Section 1.1 Review
1. A set is a collection of objects. 2. A set may be de?ned by listing the elements in it. For example, {1, 2, 3, 4} is the set consisting of the integers 1, 2, 3, 4. A set may also be de?ned by listing a property necessary for membership. For example, {x | x is a positive, real number} de?nes the set consisting of the positive, real numbers. 3. Set Z Q R Z+ Q+ R+ Z? Q? R? Znonneg Qnonneg Rnonneg Description Integers Rational numbers Real numbers Positive integers Positive rational numbers Positive real numbers Negative integers Negative rational numbers Negative real numbers Nonnegative integers Nonnegative rational numbers Nonnegative real numbers Examples of Members ?3, 2 ?3/4, 2.13074 √ ?2.13074, 2 2, 10 3/4, 2.13074 √ 2.13074, 2 ?12, ?10 ?3/8, ?2.13074 √ ?2.13074, ? 2 0, 3 0, 3.13074 √ 0, 3

14. X is a proper subset of Y if X ⊆ Y and X = Y . X is a pro