### Solving Homogeneous Linear Differential Equations with Complex Roots When dealing with homogeneous linear differential equations, we frequently encounter scenarios that require us to find the general solution of the differential equation. Consider the following second-order differential equation: \[ ay'' + by' + cy = 0 \] ### Characteristic Equation To solve this differential equation, we first form the characteristic (auxiliary) equation: \[ ar^2 + br + c = 0 \] ### Using the Quadratic Formula The roots of this characteristic equation can be found using the quadratic formula: \[ r = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] ### Nature of the Roots The nature of the roots of the characteristic equation depends on the discriminant, \( b^2 - 4ac \). 1. **Real and Distinct Roots** \( (b^2 - 4ac > 0) \) 2. **Real and Repeated Roots** \( (b^2 - 4ac = 0) \) 3. **Complex Roots** \( (b^2 - 4ac < 0) \) ### Case with Complex Roots For the case where \( b^2 - 4ac < 0 \), the roots of the characteristic equation are complex and can be expressed as: \[ r = \alpha \pm \beta i \] ### General Solution for Complex Roots The general solution for the differential equation, when the roots are complex, is: \[ y(t) = C_1 e^{\alpha t} \cos(\beta t) + C_2 e^{\alpha t} \sin(\beta t) \] where: - \( \alpha \) and \( \beta \) are real numbers derived from the roots of the characteristic equation. - \( C_1 \) and \( C_2 \) are constants determined by initial conditions. ### Example Selection Given the specific question: **What form will the solution to the differential equation be if \( b^2 - 4ac < 0 \)?** The correct answer is: \[ \boxed{y(t) = C_1 e^{\alpha t} \cos(\beta t) + C_2 e^{\alpha t} \sin(\beta t)} \] ### Explanation of the Provided Options - **First Option (Correct)**: \( y(t)

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question
See photo
### Solving Homogeneous Linear Differential Equations with Complex Roots

When dealing with homogeneous linear differential equations, we frequently encounter scenarios that require us to find the general solution of the differential equation. 

Consider the following second-order differential equation:

\[ ay'' + by' + cy = 0 \]

### Characteristic Equation
To solve this differential equation, we first form the characteristic (auxiliary) equation:

\[ ar^2 + br + c = 0 \]

### Using the Quadratic Formula
The roots of this characteristic equation can be found using the quadratic formula:

\[ r = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \]

### Nature of the Roots
The nature of the roots of the characteristic equation depends on the discriminant, \( b^2 - 4ac \). 

1. **Real and Distinct Roots** \( (b^2 - 4ac > 0) \)
2. **Real and Repeated Roots** \( (b^2 - 4ac = 0) \)
3. **Complex Roots** \( (b^2 - 4ac < 0) \)

### Case with Complex Roots
For the case where \( b^2 - 4ac < 0 \), the roots of the characteristic equation are complex and can be expressed as:

\[ r = \alpha \pm \beta i \]

### General Solution for Complex Roots
The general solution for the differential equation, when the roots are complex, is:

\[ y(t) = C_1 e^{\alpha t} \cos(\beta t) + C_2 e^{\alpha t} \sin(\beta t) \]

where:
- \( \alpha \) and \( \beta \) are real numbers derived from the roots of the characteristic equation.
- \( C_1 \) and \( C_2 \) are constants determined by initial conditions.

### Example Selection
Given the specific question:

**What form will the solution to the differential equation be if \( b^2 - 4ac < 0 \)?**

The correct answer is:

\[ \boxed{y(t) = C_1 e^{\alpha t} \cos(\beta t) + C_2 e^{\alpha t} \sin(\beta t)} \]

### Explanation of the Provided Options
- **First Option (Correct)**: \( y(t)
Transcribed Image Text:### Solving Homogeneous Linear Differential Equations with Complex Roots When dealing with homogeneous linear differential equations, we frequently encounter scenarios that require us to find the general solution of the differential equation. Consider the following second-order differential equation: \[ ay'' + by' + cy = 0 \] ### Characteristic Equation To solve this differential equation, we first form the characteristic (auxiliary) equation: \[ ar^2 + br + c = 0 \] ### Using the Quadratic Formula The roots of this characteristic equation can be found using the quadratic formula: \[ r = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] ### Nature of the Roots The nature of the roots of the characteristic equation depends on the discriminant, \( b^2 - 4ac \). 1. **Real and Distinct Roots** \( (b^2 - 4ac > 0) \) 2. **Real and Repeated Roots** \( (b^2 - 4ac = 0) \) 3. **Complex Roots** \( (b^2 - 4ac < 0) \) ### Case with Complex Roots For the case where \( b^2 - 4ac < 0 \), the roots of the characteristic equation are complex and can be expressed as: \[ r = \alpha \pm \beta i \] ### General Solution for Complex Roots The general solution for the differential equation, when the roots are complex, is: \[ y(t) = C_1 e^{\alpha t} \cos(\beta t) + C_2 e^{\alpha t} \sin(\beta t) \] where: - \( \alpha \) and \( \beta \) are real numbers derived from the roots of the characteristic equation. - \( C_1 \) and \( C_2 \) are constants determined by initial conditions. ### Example Selection Given the specific question: **What form will the solution to the differential equation be if \( b^2 - 4ac < 0 \)?** The correct answer is: \[ \boxed{y(t) = C_1 e^{\alpha t} \cos(\beta t) + C_2 e^{\alpha t} \sin(\beta t)} \] ### Explanation of the Provided Options - **First Option (Correct)**: \( y(t)
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 1 images

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,