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9.3 Geometric Sequences and Series. 9.3 Geometric Sequences. A sequence is geometric if the ratios of consecutive terms are the same. This common ratio is r. Take any two consecutive terms and divide them.
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9.3 Geometric Sequences A sequence is geometric if the ratios of consecutive terms are the same. This common ratio is r. Take any two consecutive terms and divide them.
Write the first five terms of the geometric sequence whose first term a1 = 3 and common ratio r = 2. a1 = 3 What is the 10 term? a10 = 1536 a2 = 3(21) = 6 What is the nth term of a geometric sequence? a3 = 3(22) = 12 a4 = 3(23) = 24 an = a1rn-1 a5 = 3(24) = 48
Find the 15th term of the geometric sequence whose first term is 20 and whose common ratio is 1.05. a15 = 20(1.05)14 = 39.599 Find the 12th term of the geometric sequence 5, 15, 45, ……. First, find a1 and r. a12 = 5(3)11 = 885,735
The 4th term of a geometric sequence is 125, and the 10th term is 125/64. Find the 14th term. To solve this problem let’s let the 4th term now be the first term, the 10th term the 7th term, and the 14th term be the 11th term. a1 = 125, a7 = 125/64, a11 = ? a7 = a1r6 Now we can find a11
The Sum of a Finite Geometric Sequence Find the following sum. To find the sum we must find a1, r, and n. What are they?
The Sum of an Infinite Geometric Sequence If |r| < 1, then the sum of an infinite geometric sequence is
Find the sum of the following infinite geometric sequence. 4, 4(.6), 4(.6)2, 4(.6)3,….,4(.6)n-1 What is a1 and r?