Lesson 4-6: Geometric Series

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Lesson 4-6 Geometric Series

• Advanced Math Topics
• Mrs. Mongold

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Geometric Series

• When the terms of a series form a geometric
  sequence
• Remember geometric sequences have a pattern of
  multiplying each term by the same number to get
  the next term in the sequence

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Example of Geometric Series

• NCAA tournament
• 64 teams to start
• Sequence looks like this
• 32, 16, 8, 4, 2, 1
• Series looks like this
• 32168421

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Short cut way to find Sum
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Example

• Going back seven generations, how many ancestors
  do you have? Count your parents as the first
  generation, your four grandparents as the second
  and so on.

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Sigma Notation

• Works the same way as an arithmetic series but
  will be in the explicit form for geometric series
  which is

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Example

• (-1) 3 (-9) 27 (-81) 243 (-729) 2187

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Example

• 2 4 8 16 32 64 128

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Example

• 8 4 2 1 ½ ¼