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Ch. 7 - Transcendental Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 7, Problem 7.6.53

Evaluate the integrals in Exercises 53–76.
53. ∫dx/√(9-x²)

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1
Recognize that the integral \( \int \frac{dx}{\sqrt{9 - x^2}} \) is of the form \( \int \frac{dx}{\sqrt{a^2 - x^2}} \), where \( a = 3 \).
Recall the standard integral formula: \( \int \frac{dx}{\sqrt{a^2 - x^2}} = \arcsin\left(\frac{x}{a}\right) + C \), where \( C \) is the constant of integration.
Apply the formula by substituting \( a = 3 \) into the expression, giving \( \arcsin\left(\frac{x}{3}\right) + C \).
Write the final integral expression as \( \int \frac{dx}{\sqrt{9 - x^2}} = \arcsin\left(\frac{x}{3}\right) + C \).
Remember to include the constant of integration \( C \) since this is an indefinite integral.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Integration of Functions Involving Square Roots

Integrals containing expressions like √(a² - x²) often require recognizing standard forms or using trigonometric substitution. These integrals relate to inverse trigonometric functions, which simplify the integration process.
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Inverse Trigonometric Functions

Inverse trigonometric functions such as arcsin, arccos, and arctan arise naturally when integrating functions involving square roots of quadratic expressions. For example, ∫dx/√(a² - x²) equals arcsin(x/a) + C.
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Trigonometric Substitution

Trigonometric substitution replaces variables with trigonometric expressions to simplify integrals involving radicals. For √(a² - x²), substituting x = a sin θ transforms the integral into a form easier to integrate.
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