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Interval Notation. Today you will be introduced to interval notation. Warm-Up. Solve each of the inequalities. Write your answer as an inequality and graph the solution on a number line. 1. 4x + 5 > 25 2. 5 – 5x > 4(3 – x) 3. –16 < 3x – 4 < 2 4. –2 < -2n + 1 < 7
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Interval Notation Today you will be introduced to interval notation.
Warm-Up Solve each of the inequalities. Write your answer as an inequality and graph the solution on a number line. 1. 4x + 5 > 25 2. 5 – 5x > 4(3 – x) 3. –16 < 3x – 4 < 2 4. –2 < -2n + 1 < 7 5. 3x + 2 < -10 or 2x – 4 > -4
Types of Sets • Set: a collection of elements and its symbol is { } • Subset: a part of a set. • Disjoint Sets: two sets are disjoint if they have no elements in common. • Empty Set: If a set contains no items it is called the empty set or the null set. Symbol:
Interval Notation Subsets of real numbers are placed in interval notation. • Open Intervals: (a,b) = {x: a < x < b} • Closed Intervals: [a,b] = {x: a < x < b} *a and b are referred to as endpoints. In open intervals, endpoints are NOT included whereas in closed intervals, the endpoints are included. refers to infinity - refers to negative infinity
Bounded & Unbounded Intervals Bounded Intervals: have two specific endpoints. Example: [-2, 10] or (-2, 10) or (-2,10] Unbounded Intervals: one or no specific endpoint. Example: (-, 10] or (-2, ) or (-, )
Unions & Intersections • Union: the union of two sets A and B is the set of elements that are members of A or B or both. Symbol: AB “or” • We use the term UNION, , to unite multiple intervals.
Intersections • Intersection: the intersection of two sets A and B is the set of elements that are members of BOTH A and B. Symbol: AB “and” • We use the term INTERSECTION, , to discuss the overlap of multiple intervals.
Types of Notation We use three different types of notation to represent intervals in mathematics: • interval notation • algebraic (or inequality) notation • a number line graph *You should be able to easily go from one notation to another.
Try These: I. Represent each of the following in interval notation and on a number line. 1. –6 < x < 1 2. x < 4 3. 0 < x < 5 4. x > 2 5. –5 < x < 3
Try These: II. Represent each of the following in inequality notation and on a number line. 6. [-3,2] 7. (4,7) 8. [-3,6) 9. (-, -1] 10. (7, )
Try These: III. Represent each of the following in inequality notation and in interval notation.
Try These: III. Represent each of the following in inequality notation and in interval notation.
Try These: III. Represent each of the following in inequality notation and in interval notation.
Practice with Unions IV. Find each union or intersection and then represent the result in interval notation. 16. (-2,1] [4,6] • [3,4)[6, ) • (-, -3] (-2, )
Back to the Warm-Up We can also represent the answers to the inequalities that we completed in the warm-up in interval notation. 1. 4x + 5 > 25 2. 5 – 5x > 4(3 – x) 3. –16 < 3x – 4 < 2 4. –2 < -2n + 1 < 7 5. 3x + 2 < -10 or 2x – 4 > -4
Assignment • Complete supplemental worksheet • Cover book