Chapter 6: Problem 25
Use integration by parts to find each integral. $$ \int \frac{x}{e^{2 x}} d x $$
Short Answer
Expert verified
The integral is \( -\frac{1}{2} x e^{-2x} + \frac{1}{4} e^{-2x} + C \).
Step by step solution
01
Identify Parts for Integration by Parts
Integration by parts follows the formula \( \int u \, dv = uv - \int v \, du \). We choose \( u = x \) and \( dv = \frac{1}{e^{2x}} \, dx \). This makes it easier to solve as \( u \) differentiates to a simpler form and \( dv \) integrates straightforwardly.
02
Differentiate and Integrate Parts
Calculate \( du \) by differentiating \( u \): \( du = dx \). Next, find \( v \) by integrating \( dv \): \( v = \int e^{-2x} \, dx = -\frac{1}{2} e^{-2x} \).
03
Apply the Integration by Parts Formula
Substitute \( u \), \( dv \), \( v \), and \( du \) into the integration by parts formula: \[ \int \frac{x}{e^{2x}} \, dx = -\frac{1}{2} x e^{-2x} - \int \left(-\frac{1}{2} e^{-2x}\right) \, dx \].
04
Simplify and Solve the Remaining Integral
The remaining integral to solve is \( \int \frac{1}{2} e^{-2x} \, dx \). This equals \( -\frac{1}{4} e^{-2x} \) after applying basic integration rules. Combine with the previous results to get: \[ -\frac{1}{2} x e^{-2x} + \frac{1}{4} e^{-2x} + C \].
05
Combine Terms and Write the Final Solution
The solution to the integral \( \int \frac{x}{e^{2x}} \, dx \) is \[ -\frac{1}{2} x e^{-2x} + \frac{1}{4} e^{-2x} + C \], where \( C \) is the constant of integration.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Integration Techniques
Integration techniques are methods used to evaluate integrals, which is a fundamental task in calculus. One such technique is **integration by parts**, designed to be used on products of functions.
The formula for integration by parts is: \( \int u \, dv = uv - \int v \, du \).
This technique is particularly useful when you can identify portions of the integrand as \( u \) and \( dv \) such that:
The formula for integration by parts is: \( \int u \, dv = uv - \int v \, du \).
This technique is particularly useful when you can identify portions of the integrand as \( u \) and \( dv \) such that:
- \( u \) can be easily differentiated to \( du \)
- \( dv \) can be easily integrated to find \( v \)
Calculus Integration
Calculus integration encompasses a variety of techniques to compute integrals either analytically or numerically. It is the process of finding a function whose derivative is given. This could range from simple polynomials to more complex functions like exponentials and trigonometric functions.
The purpose of integrating a function is often to find the area under a curve over a specific interval or the accumulated quantity.
In our case, **calculus integration** involves integration by parts applied to \( \int \frac{x}{e^{2x}} \, dx \). To do this effectively, understanding the relationship between differentiation and integration is crucial, as this often simplifies finding \( v \) from \( dv \), and \( du \) from \( u \).
The purpose of integrating a function is often to find the area under a curve over a specific interval or the accumulated quantity.
In our case, **calculus integration** involves integration by parts applied to \( \int \frac{x}{e^{2x}} \, dx \). To do this effectively, understanding the relationship between differentiation and integration is crucial, as this often simplifies finding \( v \) from \( dv \), and \( du \) from \( u \).
- Differentiate \( u \) to find \( du \)
- Integrate \( dv \) to obtain \( v \)
Indefinite Integrals
An indefinite integral represents a family of functions whose derivatives are equal to the function being integrated. It is written without specific bounds and includes a constant of integration \( C \).
When calculating an indefinite integral, the goal is to determine the antiderivative, a function whose derivative would return the original integrand.
For the integral \( \int \frac{x}{e^{2x}} \, dx \), after applying integration by parts, certain terms are condensed, and the result is expressed as an indefinite integral. The final answer is:
When calculating an indefinite integral, the goal is to determine the antiderivative, a function whose derivative would return the original integrand.
For the integral \( \int \frac{x}{e^{2x}} \, dx \), after applying integration by parts, certain terms are condensed, and the result is expressed as an indefinite integral. The final answer is:
- \(-\frac{1}{2} x e^{-2x} + \frac{1}{4} e^{-2x} + C \)