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Pre Calculus Sec 1.1 Real Numbers. Objectives: To review the set of Real Numbers To review the properties of Algebra To understand interval and set notation. Real Numbers. Natural Numbers: 1,2,3,4,… Integers: -,…-3,-2,-1,0,1,2,3,…
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Pre CalculusSec 1.1 Real Numbers Objectives: To review the set of Real Numbers To review the properties of Algebra To understand interval and set notation.
Real Numbers • Natural Numbers: 1,2,3,4,… • Integers: -,…-3,-2,-1,0,1,2,3,… • Rational Numbers: any # that can be written as a ratio of integers (as a fraction). • Irrational Numbers: any # that cannot be written as a fraction.
CLASS WORK • Given the set, list the elements of the set that are: • Natural numbers • Integers • Rational numbers • Irrational numbers
Properties of Real Numbers Commutative Property: a + b = b + a ab = ba order doesn’t matter Associative Property: (a+b)+c = a+(b+c) (ab)c = a(bc) order doesn’t change
Distributive Property: a(b+c) = ab + ac you can add then multiply or multiply then add.
CLASS WORK State the property of real numbers being used. 2. 3. 4.
Sets & Elements • A set is a collection of objects. - the objects are called the elements of the set. If S is a set, the notation of means that a is an element of S.
Sets & Elements means that b is not an element of S. Ex1. If Z represents the set of integers, then but
Notation of Sets • Braces { } - The set A that consists of positive integers less than 7 is • Set-builder notation – • Interval notation – These are sets of real numbers and correspond geometrically to line segments.
Union of Sets • If S and T are sets, then , represents their union. The union of sets consists of all elements in both sets. Ex 2. Find if
Intersection of Sets • The intersection of S and T is the set consisting of all elements that are in both sets. It is only what they have in common. Ex 3. Find if
CLASS WORK If find: 5. 6. 7.
CLASS WORK If find 8. 9. 10.
Intervals b b
Ex. 5 Express each interval in terms of inequalities then graph the interval. • [-1, 2) • [1.5, 4] • (-3, )
CLASS WORK Express each interval in terms of inequalities then graph the interval. 11. [2, 8) • (-, -5)
CLASS WORK Express the inequality in interval notation, then graph the interval. 13. 14.