Find the general solution for y" + 4y = sin(2t)

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

Differential 

## General Solution of the Differential Equation

**Problem Statement:**

Find the general solution for 
\[ y'' + 4y = \sin(2t) \]

**Solution:**
To solve this second-order non-homogeneous linear differential equation, we need to find the general solution, which is a combination of the homogeneous solution and a particular solution.

### 1. Homogeneous Solution
First, we solve the corresponding homogeneous equation:
\[ y'' + 4y = 0 \]

The characteristic equation is:
\[ r^2 + 4 = 0 \]

Solving for \(r\):
\[ r^2 = -4 \]
\[ r = \pm 2i \]

Thus, the general solution to the homogeneous equation is:
\[ y_h(t) = C_1 \cos(2t) + C_2 \sin(2t) \]
where \(C_1\) and \(C_2\) are arbitrary constants.

### 2. Particular Solution
Next, we find a particular solution to the non-homogeneous equation. Considering the form of the non-homogeneous term (\(\sin(2t)\)), we can assume a particular solution of the form:
\[ y_p(t) = A t \cos(2t) + B t \sin(2t) \]

Substituting \(y_p(t)\), its first, and second derivatives into the original differential equation and solving for constants \(A\) and \(B\), we obtain the particular solution.

### 3. General Solution
The general solution is then the sum of the homogeneous solution and the particular solution:
\[ y(t) = y_h(t) + y_p(t) \]
\[ y(t) = C_1 \cos(2t) + C_2 \sin(2t) + y_p(t) \]

### Conclusion
Therefore, the general solution of the given differential equation is:
\[ y(t) = C_1 \cos(2t) + C_2 \sin(2t) + y_p(t) \]
where \(C_1\) and \(C_2\) are constants determined by initial conditions, and \(y_p(t)\) is any particular solution found by substitution.
Transcribed Image Text:## General Solution of the Differential Equation **Problem Statement:** Find the general solution for \[ y'' + 4y = \sin(2t) \] **Solution:** To solve this second-order non-homogeneous linear differential equation, we need to find the general solution, which is a combination of the homogeneous solution and a particular solution. ### 1. Homogeneous Solution First, we solve the corresponding homogeneous equation: \[ y'' + 4y = 0 \] The characteristic equation is: \[ r^2 + 4 = 0 \] Solving for \(r\): \[ r^2 = -4 \] \[ r = \pm 2i \] Thus, the general solution to the homogeneous equation is: \[ y_h(t) = C_1 \cos(2t) + C_2 \sin(2t) \] where \(C_1\) and \(C_2\) are arbitrary constants. ### 2. Particular Solution Next, we find a particular solution to the non-homogeneous equation. Considering the form of the non-homogeneous term (\(\sin(2t)\)), we can assume a particular solution of the form: \[ y_p(t) = A t \cos(2t) + B t \sin(2t) \] Substituting \(y_p(t)\), its first, and second derivatives into the original differential equation and solving for constants \(A\) and \(B\), we obtain the particular solution. ### 3. General Solution The general solution is then the sum of the homogeneous solution and the particular solution: \[ y(t) = y_h(t) + y_p(t) \] \[ y(t) = C_1 \cos(2t) + C_2 \sin(2t) + y_p(t) \] ### Conclusion Therefore, the general solution of the given differential equation is: \[ y(t) = C_1 \cos(2t) + C_2 \sin(2t) + y_p(t) \] where \(C_1\) and \(C_2\) are constants determined by initial conditions, and \(y_p(t)\) is any particular solution found by substitution.
Expert Solution
steps

Step by step

Solved in 3 steps with 2 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,