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Ch. 10 - Sequences and Infinite Series
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook
Chapter 10, Problem 10.2.83a

Explain why or why not
Determine whether the following statements are true and give an explanation or counterexample.
a.If limₙ→∞aₙ = 1 and limₙ→∞bₙ = 3, then limₙ→∞(bₙ / aₙ) = 3.

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1
Recall the limit laws for sequences: if \( \lim_{n \to \infty} a_n = A \) and \( \lim_{n \to \infty} b_n = B \), and if \( A \neq 0 \), then \( \lim_{n \to \infty} \frac{b_n}{a_n} = \frac{B}{A} \).
Given \( \lim_{n \to \infty} a_n = 1 \) and \( \lim_{n \to \infty} b_n = 3 \), since \( a_n \) approaches 1 (which is not zero), the limit of the quotient should be \( \frac{3}{1} = 3 \).
Therefore, the statement \( \lim_{n \to \infty} \frac{b_n}{a_n} = 3 \) is true under these conditions.
To confirm, consider that the denominator sequence \( a_n \) does not approach zero, so division by \( a_n \) is well-defined in the limit.
Hence, the limit of the quotient is the quotient of the limits, which justifies the statement.

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Key Concepts

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

Limit of a Sequence

The limit of a sequence is the value that the terms of the sequence approach as the index goes to infinity. If a sequence converges to a limit, its terms get arbitrarily close to that limit for sufficiently large indices.
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