Find the sum of each infinite geometric series. -6 + 4 - 8/3 + 16/9 - ...
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
9. Sequences, Series, & Induction
Geometric Sequences
Problem 51
Textbook Question
The general term of a sequence is given. Determine whether the sequence is arithmetic, geometric, or neither. If the sequence is arithmetic, find the common difference; if it is geometric, find the common ratio. an = n + 5
Verified step by step guidance1
Identify the general term of the sequence: \(a_n = n + 5\).
Recall that an arithmetic sequence has a constant difference between consecutive terms, while a geometric sequence has a constant ratio between consecutive terms.
Calculate the first few terms of the sequence by substituting values of \(n\): for example, \(a_1 = 1 + 5\), \(a_2 = 2 + 5\), \(a_3 = 3 + 5\).
Find the differences between consecutive terms: \(a_2 - a_1\), \(a_3 - a_2\), and check if these differences are constant.
If the differences are constant, conclude the sequence is arithmetic and identify the common difference; if not, check the ratios \(\frac{a_2}{a_1}\), \(\frac{a_3}{a_2}\) to see if the sequence is geometric and find the common ratio if applicable.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Arithmetic Sequence
An arithmetic sequence is a sequence of numbers where the difference between consecutive terms is constant. This constant difference is called the common difference. For example, in the sequence 2, 5, 8, 11, the common difference is 3.
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Geometric Sequence
A geometric sequence is a sequence where each term after the first is found by multiplying the previous term by a constant called the common ratio. For example, in the sequence 3, 6, 12, 24, the common ratio is 2.
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General Term of a Sequence
The general term (an) of a sequence is a formula that defines the nth term in terms of n. Understanding this formula helps identify the type of sequence and calculate specific terms, differences, or ratios as needed.
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