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Ch. 10 - Infinite Sequences and Series
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 10, Problem 10.1.31

Convergence and Divergence
Which of the sequences {aₙ} in Exercises 31–100 converge, and which diverge? Find the limit of each convergent sequence.
aₙ = 2 + (0.1)ⁿ

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1
Identify the general term of the sequence: \(a_n = 2 + (0.1)^n\).
Recall that a sequence converges if its terms approach a finite limit as \(n\) approaches infinity.
Analyze the behavior of the term \((0.1)^n\) as \(n \to \infty\). Since \(0.1\) is a number between 0 and 1, \((0.1)^n\) approaches 0 as \(n\) becomes very large.
Use the limit laws to find the limit of the sequence: \(\lim_{n \to \infty} a_n = \lim_{n \to \infty} \left( 2 + (0.1)^n \right) = 2 + \lim_{n \to \infty} (0.1)^n\).
Since \(\lim_{n \to \infty} (0.1)^n = 0\), conclude that \(\lim_{n \to \infty} a_n = 2 + 0 = 2\), so the sequence converges to 2.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Sequence Convergence

A sequence converges if its terms approach a specific finite value as n approaches infinity. This limit is the value the sequence gets arbitrarily close to, indicating stability in the sequence's behavior over time.
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Limit of a Sequence

The limit of a sequence {aₙ} is the value L that the terms aₙ approach as n becomes very large. If such a limit exists and is finite, the sequence converges to L; otherwise, it diverges.
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Behavior of Exponential Terms with Base Between 0 and 1

For a term like (0.1)ⁿ, where the base is between 0 and 1, the value approaches zero as n increases. This property helps determine the limit of sequences involving such terms.
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