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Ch. 8 - Techniques of Integration
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
8장, 문제 8.8.46

In Exercises 35–68, use integration, the Direct Comparison Test, or the Limit Comparison Test to test the integrals for convergence. If more than one method applies, use whatever method you prefer.
∫ from 0 to 1 of (dt / (t - sin t))
(Hint: t ≥ sin t for t ≥ 0)

검증된 단계별 안내
1
First, analyze the behavior of the integrand near the problematic point, which is at the lower limit t = 0, because the denominator \( t - \sin t \) approaches zero there.
Use the hint \( t \geq \sin t \) for \( t \geq 0 \) to understand that the denominator \( t - \sin t \) is non-negative and approaches zero as \( t \to 0^+ \). This suggests the integrand may have a singularity at 0.
Apply the Taylor series expansion for \( \sin t \) near 0: \( \sin t = t - \frac{t^3}{6} + O(t^5) \). Substitute this into the denominator to approximate \( t - \sin t \approx \frac{t^3}{6} \) for small \( t \).
Rewrite the integrand near 0 using this approximation: \( \frac{1}{t - \sin t} \approx \frac{1}{\frac{t^3}{6}} = \frac{6}{t^3} \). This helps to compare the given integral to a simpler integral \( \int_0^1 \frac{1}{t^3} dt \).
Use the Direct Comparison Test or Limit Comparison Test by comparing \( \frac{1}{t - \sin t} \) to \( \frac{1}{t^3} \) near 0. Since \( \int_0^1 \frac{1}{t^3} dt \) diverges, conclude about the convergence or divergence of the original integral based on this comparison.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
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주요 개념

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

Improper Integrals and Convergence

An improper integral involves integration over an interval where the function is unbounded or the interval is infinite. To determine convergence, we analyze the behavior of the integrand near problematic points, such as where the denominator approaches zero. Convergence means the integral approaches a finite value.
추천 영상:
11:11
Improper Integrals: Infinite Intervals

Direct Comparison Test

The Direct Comparison Test compares the given integrand to a simpler function whose convergence behavior is known. If the integrand is less than or equal to a convergent function, the integral converges; if it is greater than or equal to a divergent function, the integral diverges. This test requires establishing inequalities between functions.
추천 영상:
09:25
Direct Comparison Test

Limit Comparison Test

The Limit Comparison Test involves taking the limit of the ratio of the given integrand to a known benchmark function as the variable approaches a critical point. If the limit is a positive finite number, both integrals share the same convergence behavior. This test is useful when direct comparison is difficult.
추천 영상:
07:45
Limit Comparison Test