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Sequences. Sequences. Objectives : 7.5.01 Identify, analyze, and create linear relations, sequences, and functions using symbols, graphs, tables, diagrams, and written descriptions. Essential Question : What is the difference between arithmetic and geometric sequences?. Sequences.
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Sequences • Objectives: • 7.5.01Identify, analyze, and create linear relations, sequences, and functions using symbols, graphs, tables, diagrams, and written descriptions. • Essential Question: • What is the difference between arithmetic and geometric sequences?
Sequences Vocabulary: • Sequence:a list or set of numbers in a certain order. • Arithmetic Sequence:a numerical pattern that increases or decreases at a constant rate or value. The difference between successive terms of the sequence is constant. (example: 2, 5, 8, 11, 14…) • Geometric Sequence:a sequence in which each term can be found by multiplying the previous term by the same number.
Sequences What Are They: • We use sequences all the time in our day to day, but in math class we will study two specific types of sequences: • 1) Arithmetic Sequences • 2) Geometric Sequences
Sequences Arithmetic Sequences: • In an arithmetic sequence, each term is found by adding the same number to the previous term. • Example: • 4, 8, 12, 16, … + 4 + 4 + 4
Sequences Geometric Sequences: • In an geometric sequence, each term is found by multiplying the previous term by the same number. • Example: • 2, 4, 8, 16, … x 2 x 2 x 2
Sequences Example 1:Identifying Sequences • Describe the pattern in the sequence and identify it as arithmetic, geometric, or neither. • Example 1: 0, 9, 18, 27, … • 0, 9, 18, 27, … +9 +9 +9 Because each term is found by adding 9 to the previous term, this is an arithmetic sequence.
Sequences Example 2:Identifying Sequences • Describe the pattern in the sequence and identify it as arithmetic, geometric, or neither. • Example 2: 2, 6, 18, 54, … • 2, 6, 18, 54, … x 3 x 3 x 3 Because each term is found by multiplying the previous number by 3, this is an geometric sequence.
Sequences Example 3:Identifying Sequences • Describe the pattern in the sequence and identify it as arithmetic, geometric, or neither. • Example 3: 0, 2, 6, 12, … • 0, 2, 6, 12, … +2 +4 +6 Because each term is found by adding two more than what was added to the previous term, this is neither.
Sequences Example 4:Identifying Sequences • Identify as arithmetic, geometric, or neither and then write the next three terms. • Example 4: 5, 5.4, 5.8, 6.2, … • 5, 5.4, 5.8, 6.2, __ , __ , __ +0.4 +0.4 +0.4 +0.4 +0.4 +0.4 This is an arithmetic sequence, in which 0.4 is added to each term. The next terms are 6.6, 7.0, and 7.4.
Sequences Real World:Construction Work • The table below shows typical costs for a construction company to rent a crane for one, two, three, or four months. Assuming that the arithmetic sequence continues, how much would it cost to rent the crane for 24 months?
Sequences Real World:Construction Work • Since the difference between any two successive costs is $15,000, the costs form an arithmetic sequence with common difference 15,000. Our solution should include an initial cost of $75,000 and an increase of $15,000 per month. Solution 1: Since the difference between any two successive costs is $15,000, the costs form an arithmetic sequence with common difference 15,000. We had an initial $75,000 + $15,000 for 23 months = $240,000
Sequences Real World:Construction Work • However, algebraically we would solve this problem using the following:
Sequences Independent Practice: Determine what kind of sequence and the rule. 1. 1, 3, 5, 7, … 2. 5, 15, 45, 135, … 3. 0.5, 1.5, 4.5, 13.5, … 4. 11, 22, 33, 44, … 5. 1, 2, 6, 24, … Arithmetic (+ 2) Geometric (x 3) Geometric (x 3) Arithmetic (+ 11) Neither
Sequences Summary: • We have studied two kinds of sequences: • Arithmetic Sequences • Each term is found by adding the same number to the previous term: • 5, 10, 15, 20, 25, … (+ 5) • Geometric Sequences • Each term is found by multiplying the previous term by the same number: • 3, 12, 48, 182, 728, … (x 4)
Sequences HOMEWORK