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 8.1.16

The integrals in Exercises 1–44 are in no particular order. Evaluate each integral using any algebraic method, trigonometric identity, or substitution you think is appropriate.
∫ (dθ / √(2θ - θ²))

검증된 단계별 안내
1
Start by examining the integral: \(\int \frac{d\theta}{\sqrt{2\theta - \theta^{2}}}\). Notice that the expression under the square root is a quadratic in \(\theta\).
Rewrite the quadratic expression inside the square root in a more recognizable form by completing the square: \(2\theta - \theta^{2} = -\left(\theta^{2} - 2\theta\right) = -\left(\theta^{2} - 2\theta + 1 - 1\right) = -\left( (\theta - 1)^{2} - 1 \right) = 1 - (\theta - 1)^{2}\).
Substitute \(x = \theta - 1\) to simplify the integral. Then, \(d\theta = dx\), and the integral becomes \(\int \frac{dx}{\sqrt{1 - x^{2}}}\).
Recognize that the integral \(\int \frac{dx}{\sqrt{1 - x^{2}}}\) is a standard form whose antiderivative is \(\arcsin x + C\).
Finally, substitute back \(x = \theta - 1\) to express the answer in terms of the original variable \(\theta\): the integral equals \(\arcsin(\theta - 1) + C\).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
7m
도움이 되었나요?

주요 개념

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

Integration by Substitution

Integration by substitution involves changing variables to simplify an integral. By letting a new variable represent a part of the integrand, the integral can often be transformed into a more manageable form. This technique is especially useful when the integrand contains composite functions.
추천 영상:
04:27
Substitution With an Extra Variable

Completing the Square

Completing the square rewrites a quadratic expression in the form ax² + bx + c as a perfect square plus or minus a constant. This method helps simplify expressions under square roots, making them easier to integrate, often leading to trigonometric substitutions.
추천 영상:
05:22
Completing the Square to Rewrite the Integrand

Trigonometric Substitution

Trigonometric substitution replaces algebraic expressions involving square roots of quadratic polynomials with trigonometric functions. This leverages identities like sin²x + cos²x = 1 to simplify integrals, especially those involving √(a² - x²), √(x² - a²), or √(x² + a²).
추천 영상:
6:04
Introduction to Trigonometric Functions