Order of Initial Conditions in PDE Solutions: How to Determine?

In summary, when solving a partial differential equation using a particular method, it is necessary to first solve the boundary value problem in order to write the solution to the temporal equation. As for the specific order in which to use the initial and boundary conditions, it does not matter in most situations. For example, in the given wave equation, the initial conditions will independently determine the constants regardless of their order.
  • #1
coverband
171
1
When solving a pde using this method how do you know what ORDER to use the initial/boundary conditions given to you?

E.g. if you are asked to solve the wave equation given u(x,0), u'(x,0), u(0,t), u(l,t) how do you know what order to use these in (particularly the first two)
 
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  • #2


You need to solve the boundary value problem first, so that you can write the solution to the temporal equation in terms of the eigenvalues of the boundary value problem.
 
  • #3


Thanks, but after you use the two boundary conditions how do you know what order to use the two initial conditions
 
  • #4
As far as situations I've seen, it doesn't matter what order you use them in. In the wave equation example you gave, the initial conditions will independently determine the constants.
 

Related to Order of Initial Conditions in PDE Solutions: How to Determine?

1. What is separation of variables?

Separation of variables is a mathematical technique used to solve certain types of differential equations. It involves expressing a multivariable function as a product of one-variable functions and then solving each function individually.

2. When is separation of variables used?

Separation of variables is typically used when solving partial differential equations involving two or more variables. It is also commonly used in physics and engineering to model and solve problems involving heat transfer, wave propagation, and diffusion.

3. How does separation of variables work?

The main idea behind separation of variables is to assume that the solution to a differential equation can be expressed as a product of functions, each of which depends on only one variable. These functions are then substituted into the differential equation, resulting in a set of simpler equations that can be solved individually. The solutions are then combined to obtain the overall solution.

4. What are the benefits of using separation of variables?

One of the main benefits of separation of variables is that it reduces a complex problem into a series of simpler ones, making it easier to solve. It also allows for the use of techniques such as integration and differentiation, which are familiar to mathematicians and scientists.

5. Are there any limitations to separation of variables?

While separation of variables is a powerful technique, it can only be applied to a specific set of differential equations. It is also important to ensure that the assumed solution satisfies any boundary conditions or initial conditions of the problem. Additionally, some problems may require more advanced techniques beyond separation of variables.

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