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Ch. 11 - Power Series
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243당신이 사용하는 게 아니라요?교과서 변경
11장, 문제 11.R.29

Power series from the geometric series Use the geometric series a Σₖ ₌ ₀ ∞ (x)ᵏ = 1/(1 - x), for |x| < 1, to determine the Maclaurin series and the interval of convergence for the following functions.


ƒ(x) = 1/(1 - x²)

검증된 단계별 안내
1
Recall the geometric series formula: \(\sum_{k=0}^{\infty} x^k = \frac{1}{1 - x}\) for \(|x| < 1\).
Notice that the given function is \(f(x) = \frac{1}{1 - x^2}\), which can be seen as \(\frac{1}{1 - (x^2)}\).
Apply the geometric series formula by substituting \(x\) with \(x^2\), so the series becomes \(\sum_{k=0}^{\infty} (x^2)^k = \sum_{k=0}^{\infty} x^{2k}\).
Write the Maclaurin series for \(f(x)\) as \(\sum_{k=0}^{\infty} x^{2k}\), which expands to \(1 + x^2 + x^4 + x^6 + \cdots\).
Determine the interval of convergence by applying the condition \(|x^2| < 1\), which simplifies to \(|x| < 1\).

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Geometric Series

A geometric series is an infinite sum of the form Σ x^k from k=0 to ∞, which converges to 1/(1 - x) when |x| < 1. This formula provides a foundation for expressing functions as power series by recognizing patterns similar to geometric series.
추천 영상:
가이드 코스
06:00
Geometric Series

Maclaurin Series

The Maclaurin series is a special case of the Taylor series centered at zero, representing a function as an infinite sum of its derivatives at zero multiplied by powers of x. It allows us to express functions as power series expansions around x = 0.
추천 영상:
08:26
Convergence of Taylor & Maclaurin Series

Interval of Convergence

The interval of convergence is the set of x-values for which a power series converges to the function it represents. For geometric series, this interval is determined by the condition |x| < 1, and it must be adjusted when the series involves expressions like x².
추천 영상:
08:44
Interval of Convergence