Finding the particular/complementary solution from a laplace transform

In summary, determining which parts of a total solution correspond to the complementary solution and particular solution is a matter of choice and cannot be determined objectively.
  • #1
eggshell
1
0
Say you find the laplace transform V(s) and want to switch it back to the time domain, once you've done this, how do you determine which parts of the total solution correspond to the complementary solution and particular solution respectively? Do you just find which parts approach zero as time increases to infinity, and label that as the complementary, or is there more to it than that?
 
Physics news on Phys.org
  • #2
Strictly speaking, you can't. If, for example, y(x)= Cf(x)+ Dg(x)+ h(x) is a solution to the differential equation, where C and D are undetermined constants, so that Cf(x)+ Dg(x) is the "complimentary solution" and h(x) is the "particular solution, we could just as easily write y(x)= (C- 1)f(x)+ (D- 2)g(x)+ (f(x)+ 2g(x)+ h(x)) so that (C- 1)f(x)+ (D- 2)g(x) is the "complimentary solution" and f(x)+ 2g(x)+ h(x) is the "particular solution". In other words, what part of a solution is "complimentary" and which is "particular" is purely a matter of choice.
 

Related to Finding the particular/complementary solution from a laplace transform

1. How do you find the particular solution from a Laplace transform?

To find the particular solution from a Laplace transform, you need to first take the Laplace transform of the given differential equation. Then, use algebraic manipulation to solve for the particular solution, which will be in terms of the Laplace variable s. Finally, take the inverse Laplace transform to get the particular solution in terms of the original variable.

2. What is the difference between the particular and complementary solution in Laplace transform?

The particular solution is the solution that satisfies the given initial conditions and is obtained by taking the inverse Laplace transform of the transformed equation. It is specific to the given initial conditions and represents the unique solution to the differential equation. The complementary solution, on the other hand, is the solution that satisfies the homogeneous version of the differential equation and is obtained by solving the transformed equation without considering the initial conditions. It represents the general solution to the differential equation.

3. Can you use Laplace transform to solve any type of differential equation?

No, Laplace transform can only be used to solve linear differential equations with constant coefficients. It cannot be used to solve non-linear or variable coefficient differential equations.

4. How do you handle initial conditions when finding the particular solution using Laplace transform?

To handle initial conditions, you need to consider them when taking the inverse Laplace transform of the transformed equation. This will result in an additional term in the particular solution, known as the initial value term, which is used to satisfy the given initial conditions.

5. Can Laplace transform be used to solve differential equations with discontinuous functions?

Yes, Laplace transform can be used to solve differential equations with discontinuous functions, as long as the discontinuity is piecewise continuous. In such cases, the Laplace transform can be taken piecewise and then the solutions can be combined to get the overall solution.

Similar threads

  • Differential Equations
2
Replies
52
Views
963
Replies
3
Views
2K
  • Differential Equations
Replies
5
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
1K
  • Differential Equations
Replies
5
Views
4K
Replies
4
Views
2K
  • Set Theory, Logic, Probability, Statistics
Replies
6
Views
1K
  • Differential Equations
Replies
2
Views
2K
  • Electrical Engineering
Replies
5
Views
1K
  • Differential Equations
Replies
1
Views
3K
Back
Top