Solving the PDE Wave Equation - A_n & B_n Terms

In summary, the conversation discussed using an infinite number of A's and B's in Fourier analysis to solve linear ODE's and PDE's. This technique is well-suited for infinite-dimensional solution spaces and involves using initial and boundary conditions to solve for coefficients in an infinite sum. The speaker suggests that if this is confusing, the listener may not be ready for the topic.
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  • #2
Putting a countable infinity of A's and B's instead of only 2 values A and B is a standard technique in Fourier analysis, which is particulary well suited for linear ODE's/PDE's. That is you rightfully assume that, because the linear/vector space of solutions is infinite dimensional, there is one (generally different) coefficient for each basis vector of the solution space, hence the infinite summation.
 
  • #3
Which part of it do you not understand.
This is how a homogenous linear PDE is usually solved:
1.Seperate equation (possible for many of the usual PDEs)
2.Solve the equations to get a "basis"
3.Write an infinite sum with them
4.Use the imposed initial/boundary conditions to solve for the coefficients of the linearly independent solutions with the generalized Fourier's trick

If none of that made sense to you, then you are not ready for that book.
 

1. What is the wave equation in PDE?

The wave equation in PDE (partial differential equations) is a mathematical equation that describes the behavior of waves, such as sound waves or electromagnetic waves. It is a second-order linear partial differential equation that relates the second derivative of a function with respect to time to its second derivatives with respect to space.

2. What are the A_n and B_n terms in the solution of the wave equation?

The A_n and B_n terms in the solution of the wave equation represent the amplitude and phase of the wave, respectively. These terms are determined by the initial conditions of the wave and can be used to find the complete solution of the equation.

3. How do you solve the PDE wave equation using the A_n and B_n terms?

To solve the PDE wave equation using the A_n and B_n terms, you first need to determine the initial conditions of the wave. Then, using these conditions, you can find the values of the A_n and B_n terms. Finally, you can combine these terms with the general solution of the wave equation to obtain the specific solution for the given initial conditions.

4. What are the boundary conditions for the PDE wave equation?

The boundary conditions for the PDE wave equation are the conditions that must be satisfied at the boundaries of the domain in which the wave is propagating. These conditions can be either of two types: Dirichlet boundary conditions, where the value of the solution is specified at the boundary, or Neumann boundary conditions, where the derivative of the solution is specified at the boundary.

5. What are some real-life applications of the PDE wave equation?

The PDE wave equation has many real-life applications, including the study of sound and light waves, electromagnetic fields, and vibrations in solid structures. It is also used in fields like acoustics, optics, seismology, and engineering to model and understand wave phenomena and design systems that utilize waves.

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