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Ch. 10 - Infinite Sequences and Series
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 10, Problema 10.1.36

Convergence and Divergence
Which of the sequences {aₙ} in Exercises 31–100 converge, and which diverge? Find the limit of each convergent sequence.
aₙ = (n + 3) / (n² + 5n + 6)

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1
Identify the given sequence: \(a_n = \frac{n + 3}{n^2 + 5n + 6}\).
To analyze convergence or divergence, examine the behavior of \(a_n\) as \(n\) approaches infinity, i.e., find \(\lim_{n \to \infty} a_n\).
Since the sequence is a rational function of \(n\), compare the degrees of the numerator and denominator polynomials. The numerator is degree 1, and the denominator is degree 2.
Divide both numerator and denominator by the highest power of \(n\) in the denominator, which is \(n^2\), to simplify the limit expression: \(a_n = \frac{\frac{n}{n^2} + \frac{3}{n^2}}{\frac{n^2}{n^2} + \frac{5n}{n^2} + \frac{6}{n^2}} = \frac{\frac{1}{n} + \frac{3}{n^2}}{1 + \frac{5}{n} + \frac{6}{n^2}}\).
Evaluate the limit by letting \(n\) approach infinity, noting that terms with \(\frac{1}{n}\) and \(\frac{1}{n^2}\) approach zero, and conclude whether the sequence converges or diverges based on this limit.

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