Chapter 8: Problem 15
Solve the initial-value problem. $$ y^{\prime}=e^{3 x}+1 ; y(0)=2 $$
Short Answer
Expert verified
The solution is \( y = \frac{e^{3x}}{3} + x + \frac{5}{3} \).
Step by step solution
01
- Identify the Type of Differential Equation
The given differential equation is a first-order linear differential equation: \( y' = e^{3x} + 1 \)
02
- Integrate Both Sides
To solve for \( y(x) \), integrate both sides of the equation with respect to \( x \): \( y = \int (e^{3x} + 1) \, dx \)
03
- Solve the Integral
Integrate each term separately: \( y = \int e^{3x} \, dx + \int 1 \, dx \) The integral of \( e^{3x} \) is \( \frac{e^{3x}}{3} \), and the integral of 1 is \( x \). Therefore, \( y = \frac{e^{3x}}{3} + x + C \)
04
- Apply the Initial Condition
Use the initial condition \( y(0) = 2 \) to solve for \( C \): \( 2 = \frac{e^{3(0)}}{3} + 0 + C \) Simplifying, we get \( 2 = \frac{1}{3} + C \) Thus, \( C = 2 - \frac{1}{3} = \frac{6}{3} - \frac{1}{3} = \frac{5}{3} \)
05
- Write the Final Solution
Substitute \( C \) back into the general solution: \( y = \frac{e^{3x}}{3} + x + \frac{5}{3} \)
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
initial-value problem
An initial-value problem is a type of differential equation that comes with extra information. This extra information is called an 'initial condition.' It gives the value of the function at a specific point, usually denoted as \( y(x_0) = y_0 \). For example, in this problem, the initial condition is \( y(0) = 2 \). This helps us find a specific solution to the differential equation, not just a general one.
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So imagine you're looking for a treasure hidden somewhere on a map (your general solution). The initial condition is like a clue that zeroes in on the exact location of the treasure (your specific solution). Typical steps involve:
.
So imagine you're looking for a treasure hidden somewhere on a map (your general solution). The initial condition is like a clue that zeroes in on the exact location of the treasure (your specific solution). Typical steps involve:
- First, solve the differential equation as if there is no initial condition.
- Second, use the initial condition to find any constants.
- Finally, write your specific solution incorporating this initial value.
integration
Integration is a fundamental concept in calculus that helps us solve differential equations. In essence, it is the reverse process of differentiation. When we integrate, we're essentially finding a function whose derivative matches a given function.
In the given problem, we need to integrate the right side of the equation \( y' = e^{3x} + 1 \).
Step-by-Step Integration:
In the given problem, we need to integrate the right side of the equation \( y' = e^{3x} + 1 \).
Step-by-Step Integration:
- First, separate the integrals: \( y = \int (e^{3x} + 1) \, dx \).
- Then, integrate each term separately: \( y = \int e^{3x} \, dx + \int 1 \, dx \).
- The integral of \( e^{3x} \) is \( \frac{e^{3x}}{3} \), and the integral of 1 is \( x \).
differential equations
Differential equations are equations that involve functions and their derivatives. They play a crucial role in modeling real-world phenomena, such as population growth, electrical circuits, and motion. In this case, we're dealing with a first-order linear differential equation.
First-order linear differential equations have the standard form: \( y' + P(x)y = Q(x) \). However, here the equation is already simplified to \( y' = e^{3x} + 1 \). Because the derivative (\( y' \)) is expressed in terms of \( x \) alone, it narrows down our approach.
Specific Steps:
First-order linear differential equations have the standard form: \( y' + P(x)y = Q(x) \). However, here the equation is already simplified to \( y' = e^{3x} + 1 \). Because the derivative (\( y' \)) is expressed in terms of \( x \) alone, it narrows down our approach.
Specific Steps:
- The first step involves treating the differential equation as a problem of finding an antiderivative.
- We perform integration to determine a general solution.
- Finally, applying the initial condition points us to the specific solution within the general family.