Numerical solution for an integral equation?

In summary, the equation is $\frac{d^2 F(t)}{dt^2}=const*\int_{t'}\frac{sin(F(t)-F(t'))}{(t-t')^{2k}}dt'$ where $F(t)=-arctan(\frac{t}{t_0}).$ There is a specific case, when $K=1$, there is an analytical solution: $F(t)=2arctan(\frac{t}{t_0}).$ Unfortunately, two main things will help me with solving this equation - finding the name of the category of the equation and finding the numerical solution.
  • #1
Asban
7
0
Hello,

I have been encountered an integral equation that I need to solve\evaluate numericly and I didn't find anything like it in my search yet.

The equation:

\frac{d^2 F(t)}{dt^2}=const*\int_{t'}\frac{sin(F(t)-F(t'))}{(t-t')^{2k}}dt'

If it helps there is a specific case, when K=1 there is an analitical solution: F(t)=2arctan(\frac{t}{t_0}).

For now, two mainly things will help me:

1: What is the exact name of category of this integral equation?
2: What is the name of the numerical solution that solve it, or solve something similar to this equation and where should I start looking?

Thank you
Ofek
 
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  • #2
Asban said:
Hello,

I have been encountered an integral equation that I need to solve\evaluate numericly and I didn't find anything like it in my search yet.

The equation:

$$\frac{d^2 F(t)}{dt^2}=const*\int_{t'}\frac{sin(F(t)-F(t'))}{(t-t')^{2k}}dt'$$
I don't understand your notation for the integral...?
 
  • #3
If I understant your question, the range is from 0 to infinity for all practical purposes but in general is suppose to be indefinite integral.
 
  • #4
Asban said:
If I understant your question, the range is from 0 to infinity for all practical purposes but in general is suppose to be indefinite integral.
Is there a reason you put the t-prime on the bottom part of the integral, then? :confused:

Also, does your t-prime imply the derivative of t, or is that a separate variable? Your notation is confusing.
 
  • #5
t and t' are different parameters, so as you see in the right hand side t acts as a constant in the integral,
but still in the right hand side there is a 2nd derivative of F with respect to the parameter t.

I need to evaluate numericly the function F(t) that solve this equation.
 
  • #6
If you were to sort out what that integral means, you might have some better luck. You can't do an integral numerically unless it has specific limits. So what you mean by putting the t' by the integral sign has to be made clear.

After that, round up the usual suspects. Look at things like a Laplace transform to try to get rid of the 2nd derivative. Look at taking some derivative of the entire equation to convert it to a differential equation without any integrals. Look at things like Gaussian quadrature to convert the integral to a set of valuations of F(t) with appropriate coefficients. Look up ways to numerically solve differential equations. You could start with a book like _Numerical Recipes in C_ (or Fortran if you prefer) for introductory methods.
Dan
 

FAQ: Numerical solution for an integral equation?

What is an integral equation?

An integral equation is a mathematical equation that involves an unknown function within an integral. It is used to describe relationships between known functions and unknown functions.

What is a numerical solution for an integral equation?

A numerical solution for an integral equation is an approximate solution that is obtained using numerical methods. It involves breaking the integral equation into smaller parts and using numerical techniques to solve each part, resulting in an approximate solution.

Why is a numerical solution needed for an integral equation?

Most integral equations cannot be solved analytically, meaning an exact solution cannot be found. Therefore, a numerical solution is needed to obtain an approximate solution to the equation.

What are some common numerical methods used for solving integral equations?

Some common numerical methods used for solving integral equations include the trapezoidal rule, Simpson's rule, and Gaussian quadrature. These methods involve approximating the integral using discrete points and then using numerical techniques to solve for the unknown function.

How accurate is a numerical solution for an integral equation?

The accuracy of a numerical solution for an integral equation depends on the chosen numerical method and the number of intervals used in the approximation. Generally, the more intervals used, the more accurate the solution will be. However, it is important to note that a numerical solution is always an approximation and may not provide an exact solution.

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