Skip to main content
Ch. 8 - Techniques of Integration
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
8장, 문제 8.8.30

The integrals in Exercises 1–34 converge. Evaluate the integrals without using tables.
∫₂⁴ dt / [t√(t² − 4)]

검증된 단계별 안내
1
Identify the integral to solve: \(\int_{2}^{4} \frac{dt}{t \sqrt{t^{2} - 4}}\).
Recognize that the integrand contains a square root of the form \(\sqrt{t^{2} - a^{2}}\), suggesting a trigonometric substitution. Use the substitution \(t = 2 \sec(\theta)\), where \(a = 2\).
Compute the differential \(dt\) in terms of \(d\theta\): since \(t = 2 \sec(\theta)\), then \(dt = 2 \sec(\theta) \tan(\theta) d\theta\).
Rewrite the integral in terms of \(\theta\) by substituting \(t\), \(dt\), and simplifying the expression under the square root: \(\sqrt{t^{2} - 4} = \sqrt{4 \sec^{2}(\theta) - 4} = 2 \tan(\theta)\).
Change the limits of integration from \(t\) to \(\theta\) using \(t = 2 \sec(\theta)\), then simplify the integral and integrate with respect to \(\theta\).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
6m
도움이 되었나요?

주요 개념

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

Improper Integrals and Convergence

Understanding when an integral converges is crucial, especially for integrals with infinite limits or integrands with singularities. In this problem, the integral is definite and the integrand is continuous on [2,4], ensuring convergence. Recognizing convergence allows safe evaluation without concern for divergence.
추천 영상:
가이드 코스
11:11
Improper Integrals: Infinite Intervals

Trigonometric Substitution

Trigonometric substitution is a technique used to simplify integrals involving expressions like √(t² − a²). By substituting t = a sec(θ), the radical simplifies using trigonometric identities, making the integral easier to evaluate. This method transforms the integral into a trigonometric integral that can be integrated directly.
추천 영상:
가이드 코스
6:04
Introduction to Trigonometric Functions

Integration Techniques for Rational Functions

Integrals involving rational functions combined with radicals often require algebraic manipulation or substitution to simplify. Recognizing the structure of the integrand, such as t in the denominator and a radical in the denominator, guides the choice of substitution and integration steps to find an explicit antiderivative.
추천 영상:
6:04
Intro to Rational Functions