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Ch. 8 - Integration Techniques
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243당신이 사용하는 게 아니라요?교과서 변경
8장, 문제 8.2.59b

59. Two Methods
b. Evaluate ∫(x / √(x + 1)) dx using substitution.

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Identify the integral to solve: \(\int \frac{x}{\sqrt{x + 1}} \, dx\).
Choose a substitution to simplify the integral. Let \(u = x + 1\), so that \(du = dx\) and \(x = u - 1\).
Rewrite the integral in terms of \(u\): replace \(x\) with \(u - 1\) and \(dx\) with \(du\), giving \(\int \frac{u - 1}{\sqrt{u}} \, du\).
Split the integral into two simpler integrals: \(\int \frac{u}{\sqrt{u}} \, du - \int \frac{1}{\sqrt{u}} \, du\), which simplifies to \(\int u^{1/2} \, du - \int u^{-1/2} \, du\).
Integrate each term using the power rule for integrals: \(\int u^{n} \, du = \frac{u^{n+1}}{n+1} + C\), then substitute back \(u = x + 1\) to express the answer in terms of \(x\).

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주요 개념

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

Integration by Substitution

Integration by substitution is a technique used to simplify integrals by changing variables. It involves choosing a substitution that transforms the integral into a simpler form, often by letting a part of the integrand equal a new variable. This method is especially useful when the integral contains a composite function.
추천 영상:
04:27
Substitution With an Extra Variable

Algebraic Manipulation of Integrands

Before applying substitution, it is often necessary to rewrite the integrand in a form that makes substitution straightforward. This may involve factoring, expanding, or expressing parts of the integrand in terms of the substitution variable. Proper manipulation helps in identifying the correct substitution and simplifies the integration process.
추천 영상:
05:22
Completing the Square to Rewrite the Integrand

Definite and Indefinite Integrals

Understanding the difference between definite and indefinite integrals is crucial. An indefinite integral represents a family of functions plus a constant of integration, while a definite integral computes the area under a curve between two limits. In substitution, adjusting the limits or adding the constant is important depending on the integral type.
추천 영상:
05:43
Definition of the Definite Integral