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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 7.2.41

Evaluate the integrals in Exercises 39–56.
41. ∫2y dy/(y²-25)

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1
Identify the integral to solve: \(\int \frac{2y}{y^{2} - 25} \, dy\).
Recognize that the denominator is a quadratic expression that can be factored as \(y^{2} - 25 = (y - 5)(y + 5)\), but before factoring, check if substitution is more straightforward.
Use substitution by letting \(u = y^{2} - 25\), then compute \(du = 2y \, dy\), which matches the numerator times \(dy\) exactly.
Rewrite the integral in terms of \(u\): \(\int \frac{2y}{y^{2} - 25} \, dy = \int \frac{1}{u} \, du\).
Integrate \(\int \frac{1}{u} \, du\) to get \(\ln|u| + C\), then substitute back \(u = y^{2} - 25\) to express the answer in terms of \(y\).

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Key Concepts

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

Integration of Rational Functions

This involves integrating functions expressed as the ratio of two polynomials. Techniques often include algebraic manipulation such as factoring or partial fraction decomposition to simplify the integral into manageable parts.
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Intro to Rational Functions

Partial Fraction Decomposition

A method used to break down complex rational expressions into simpler fractions that are easier to integrate. It is especially useful when the denominator can be factored into linear or quadratic terms.
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Partial Fraction Decomposition: Distinct Linear Factors

Substitution Method

A technique where a substitution is made to simplify the integral, often by letting a part of the integrand equal a new variable. This can transform the integral into a basic form that is straightforward to evaluate.
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