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Ch. 8 - Techniques of Integration
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 8, Problem 8.2.16

Evaluate the integrals in Exercises 1–24 using integration by parts.
∫ p⁴ e^(-p) dp

Verified step by step guidance
1
Identify the integral to solve: \(\int p^{4} e^{-p} \, dp\).
Recall the integration by parts formula: \(\int u \, dv = uv - \int v \, du\).
Choose \(u\) and \(dv\) wisely. Let \(u = p^{4}\) (a polynomial) and \(dv = e^{-p} \, dp\) (an exponential function).
Compute \(du\) and \(v\): differentiate \(u\) to get \(du = 4p^{3} \, dp\), and integrate \(dv\) to get \(v = -e^{-p}\).
Apply the integration by parts formula: substitute \(u\), \(v\), \(du\), and \(dv\) into \(\int u \, dv = uv - \int v \, du\), then simplify and repeat integration by parts on the resulting integral as needed until the polynomial term is fully reduced.

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Key Concepts

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

Integration by Parts

Integration by parts is a technique based on the product rule for differentiation. It transforms the integral of a product of functions into simpler integrals using the formula ∫u dv = uv - ∫v du. Choosing u and dv wisely simplifies the problem, especially when one function becomes simpler upon differentiation.
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Polynomial and Exponential Functions

Understanding the behavior of polynomial functions like p⁴ and exponential functions like e^(-p) is crucial. Polynomials reduce in degree when differentiated, while exponentials maintain their form. This interplay makes integration by parts effective for integrals involving their products.
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Repeated Application of Integration by Parts

When integrating products involving high-degree polynomials, integration by parts often needs to be applied multiple times. Each iteration reduces the polynomial's degree by one, gradually simplifying the integral until it becomes straightforward to evaluate.
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