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Homework. Review notes Complete Worksheet #1. Homework. Let A = { a,b,c,d }, B = { a,b,c,d,e }, C = { a,d }, D = {b, c} Describe any subset relationships. 1. A; D. Homework. Let E = {even integers}, O = {odd integers}, Z = {all integers}
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Homework • Review notes • Complete Worksheet #1
Homework Let A = {a,b,c,d}, B = {a,b,c,d,e}, C = {a,d}, D = {b, c} Describe any subset relationships. 1. A; D
Homework Let E = {even integers}, O = {odd integers}, Z = {all integers} Find each union, intersection, or complement. 5.
Homework State whether each statement is true or false. 9. - False
Homework If A = {1, 2, 3, 4}, B = {1, 4, 6, 8}, C = {2, 4, 5, 8, 10} and U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, find: 13.
Homework If A = {1, 2, 3, 4}, B = {1, 4, 6, 8}, C = {2, 4, 5, 8, 10} and U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, find: 17. A’
Homework If A = {1, 2, 3, 4}, B = {1, 4, 6, 8}, C = {2, 4, 5, 8, 10} and U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, find: 21.
Homework If A = {1, 2, 3, 4}, B = {1, 4, 6, 8}, C = {2, 4, 5, 8, 10} and U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, find: 25.
Homework List all subsets of each set. 29. {4}
Homework The power set of a set A, denoted by P (A) is the set of all subsets of A. Tell how many members the power set of each set has. 33. {4} The power set of A has 21 = 2 members
Homework State whether each statement is true or false. 1. 4 is an even number and 5 is an odd number – True
Homework Find and graph each solution set over R; i.e., p, q, and p Λ q 5. p: x > 0; q: 2x < 6 → p: x > 0; q: x < 3 ο-------------ο ο---→ ←---ο -----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|---- -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7
Homework Find and graph each solution set over R; i.e., p, q, and p Λ q 9 p: 4t – 5 ≥ 3; q: 3t + 5 ≤ 26 → p: 4t ≥ 8; q: 3t ≤ 21 → p: t ≥ 2; q: t ≤ 7 ●---------------------● ●------→ ←------● -----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|---- -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7
Homework Find and graph each solution set over R; i.e., p, q, and p ν q 13. p: 3w – 1 > 5; q: 4w +3 ≤ -1 → p: 3w > 6; q: 4w ≤ - 4 → p: w > 2; q: w ≤ -1 ←------● ο------→ ←------● ο------→ -----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|---- -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7
Homework Write the negation of each sentence. 17. There is a positive square root of 2. There is not a positive square root of 2.
Homework Write the negation of each sentence. 21.
Homework 25. Find and graph on a number line the solution set over R of the negation of the conjunction 2x < -4 or 3x > 6 → 2x ≥ -4 and 3x ≤ 6 → x ≥ -2 and x ≤ 2 ●------------● -----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|---- -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7
Homework State whether each sentence over is an identity, a contradiction, or a sentence that is sometimes true and sometimes false. 29.
Homework State whether each sentence over is an identity, a contradiction, or a sentence that is sometimes true and sometimes false. 33.
Foundations of Real Analysis Conditional Sentences Addition and Multiplication Properties of Real Numbers
Conditional Sentence Conditional sentence – sentence in which there is a dependency of one sentence on another; if p and q are sentences, a conditional sentence relating them is “if p, then q” (p → q) Conditional sentences, by definition, are always true except when p is true and q is false Converse – the opposite dependency of a conditional sentence, the converse of p → q is q → p (“if q, then p”) Biconditional sentences are true only when both p and q are true or both p and q are false Contrapositive – statement q’ → p’ is the contrapositive of p → q
Example #1 State whether the conditional sentence is true or false 2. If 12 is a multiple of 6, then 24 is a multiple of 6
Example #2 Give the converse of the conditional sentence and state if it is sometimes, always, or never true. 6. If 2 is a factor of an integer, then 2 is a factor of the square of that integer.
Example #3 Give the converse of the conditional sentence and state if it is sometimes, always, or never true. 10. If x2 < 0, then x4 ≥ 0
Example #4 State the contrapositive for each conditional sentence. 14. If ab = ac and a ≠ 0, then b = c.
Formal Mathematical Systems A formal mathematical system consists of: • Undefined objects • Postulates or axioms • Definitions • Theorems
Axioms of Equality Axioms of Equality (for all real numbers a, b, and c) : • Reflexive Property:a = a • Symmetric Property: If a = b, then b = a • Transitive Property: If a = b and b = c, then a = c
Substitution Axiom Substitution Axiom: If a = b, then in any true sentence involving a, we may substitute b for a, and obtain another true sentence
Axioms of Addition Closure For all real numbers a and b, a + b is a unique real number Associative For all real numbers a, b, and c Additive Identity There exists a unique real number 0 (zero) such that for every real number a. Additive Inverses For each real number a, there exists a real number – a (the opposite of a) such that Commutative For all real numbers a and b,
Axioms of Multiplication Closure For all real numbers a and b, ab is a unique real number Associative For all real numbers a, b, and c Multiplicative Identity There exists a unique real number 1 (one) such that for every real number a. Multiplicative Inverses For each real number a, there exists a real number (the reciprocal of a) such that Commutative For all real numbers a and b,
Distributive Axiom of Multiplication over Addition For all real numbers a, b, and c,
Definitions Subtraction : Division: provided b ≠ 0
Theorem One • For all real numbers a, b, and c: • a = b if and only if a + c = b + c Cancellation Law of Addition • a = b if and only if ac = bc (c ≠ 0) Cancellation Law of Multiplication • If a = b, – a = – b • – ( – a) = a • a∙0 = 0 • – 0 = 0 • – a = – 1(a)
Theorem One Continued • For all real numbers a, b, and c: • – ab = a (– b) = – a (b) • – (a + b) = – a + ( – b) • If a ≠ 0,
Theorem Two For all real numbers a and b: ab = 0 if andonly if a = 0 and/or b = 0
Example #5 Name the axiom, theorem, or definition that justifies each step. 2. If a = b, then a2 = b2 Proof: a = b aa = ab ab = bb aa = bb a2 = b2
Example #6 Solve over R. 6.
Example #7 Solve over R. 10.
Example #7 State whether each set is closed under (a) addition and (b) multiplication. If not, give an example. 14. {1}
Homework • Review notes • Complete Worksheet #2