Solving 2nd order differential equation

Click For Summary
SUMMARY

The discussion focuses on solving a second-order differential equation, specifically addressing the homogeneous and inhomogeneous solutions. The characteristic equation yields roots of \( e^{ix} \) and \( e^{-ix} \), leading to the general solution \( A \cos{x} + B \sin{x} \). A particular solution is identified as \( C = -1 \), resulting in the complete inhomogeneous solution \( A \cos{x} + B \sin{x} - 1 \). Participants emphasize the importance of verifying the solution against the original differential equation and initial conditions.

PREREQUISITES
  • Understanding of second-order differential equations
  • Familiarity with characteristic equations and their roots
  • Knowledge of homogeneous and inhomogeneous solutions
  • Ability to verify solutions against initial conditions
NEXT STEPS
  • Study methods for solving second-order differential equations
  • Learn about the application of the Wronskian in determining linear independence
  • Explore the use of Laplace transforms for solving differential equations
  • Investigate initial value problems and their solution verification techniques
USEFUL FOR

Students and educators in mathematics, particularly those focusing on differential equations, as well as engineers and physicists applying these concepts in practical scenarios.

Pushoam
Messages
961
Reaction score
53

Homework Statement


upload_2017-12-27_23-44-42.png


Homework Equations

The Attempt at a Solution



For the homogeneous equation, I have got the the root of the characteristic equation as ## e^{ix}, e^{-ix} ## .

So, the corresponding solution is ## B \sin{ x} + A \cos{ x} ## .

Then, I took the particular solution as C.

Putting C in the differential equation , I get C = -1.

So, the inhomogeneous solution is ## A \cos{ x} + B \sin{ x} – 1 ## , i.e. option(e).

Is this correct?
 

Attachments

  • upload_2017-12-27_23-44-42.png
    upload_2017-12-27_23-44-42.png
    7 KB · Views: 1,038
  • Like
Likes   Reactions: scottdave
Physics news on Phys.org
Looks great. You can plug it into the original differential equation to make sure that your solution satisfies it.
 
  • Like
Likes   Reactions: Pushoam
Pushoam said:
So, the inhomogeneous solution is ## A \cos{ x} + B \sin{ x} – 1 ## , i.e. option(e).
Is this correct?
You shouldn't need to ask this. Along the lines of @scottdave's advice, whenever you get a solution to a diff. equation, you should get in the habit of checking. That way you'll know whether your answer is correct. For an initial value problem, check that 1) your solution satisfies the initial condition, and 2) your solution satisifies the differential equation.
 
  • Like
Likes   Reactions: Pushoam

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
Replies
3
Views
2K
Replies
1
Views
1K
Replies
2
Views
2K
Replies
7
Views
2K
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
8
Views
1K