9.3.notebook
April 28, 2014
9.3 Geometric Sequences and Series
Objective: Students will recognize, write, and find the nth term of geometric
sequences.
Geometric sequences have a common ratio (r) between consecutive terms.
Ex.) Find the common ratio of the geometric sequence 2n.
b.) Find the common ratio of the geometric sequence 4(3n).
c.) Find the common ratio of the geometric sequence (‐1/3)n.
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9.3.notebook
April 28, 2014
The nth term of a geometric sequence has the form
where r is the common ratio.
Ex.) Write the first five terms of the geometric sequence whose first term is a1 = 3
and whose common ratio is r = 2.
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9.3.notebook
April 28, 2014
Ex.) Find the 15th term of the geometric sequence whose first term is 20 and
whose common ratio is 1.05
Ex.) Find a formula for the nth term of the following geometric sequence. What is
the 9th term of the sequence?
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9.3.notebook
April 28, 2014
Ex.) The fourth term of a geometric sequence is 125 and the 10th term is 125/64. Find the 14th term.
HW: p. 644 #3‐18 m3, 28 ‐ 42 even
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