Talk:Method of undetermined coefficients

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I can solve A_n = A A_{n-1} + B A_{n-2}, but how do I go about solving A_n = A A_{n-1} + B A_{n-2} + k?

Many thanks in advance for your help. Pcb21| Pete 13:49, 22 July 2005 (UTC)

Is that different "A"s you're talking about, "A" and "A_n"? Reorder the equation to get A_n - a A_{n-1} - b A_{n-2} = k. Find solutions for the inhomogeneous and the homogeneous difference equation. Notice that you have a difference eq'n, not a differential eq'n. Probably this is too late, as the stochastics class is already over (right guess?) 134.83.1.225 15:35, 12 December 2005 (UTC)

Contents 1 Strange Roots yield different answers 2 particular solution 3 General theorem 4 Example sections 5 Difference Equations

[edit] Strange Roots yield different answers

Should it be noted that when differential equations yield repeated or imaginary roots the form of the 'guess' changes? --Bmalicoat 05:26, 1 March 2006 (UTC)

Yes, it should. Also, more of the theory should be explained. Ruakh 05:56, 1 March 2006 (UTC)

[edit] particular solution

The examples make a pat description of an extremely simple problem, making it difficult to see how one would provide forms for the particular solutions of more complex equations. The difficult example, on the other hand, is overly complex for some cases.

[edit] General theorem

why no add a complitely general solution that can work as a theorem/formula into which you can simply plug in? —The preceding unsigned comment was added by 128.59.154.21 (talk) 01:50, 29 March 2007 (UTC).

There is no formula which yields the solution to any inhomogeneous differential equation. The completely general solution is simply what is already described here: find a solution to the complementary equation (i.e., the homogeneous part), and then find a particular solution to the inhomogeneous version. Their sum is the general solution. Rundquist 00:33, 24 June 2007 (UTC)

[edit] Example sections

Is there any particular reason that this article contains two sections for examples? If they are to be combined, should it be before or after the "Typical forms" section? Also, anybody who knows more about the relationship between this method and the annihilator method, please contribute. Rundquist 00:38, 24 June 2007 (UTC)

[edit] Difference Equations

It was mentioned that this method can be used to solve difference equations. Is there an example of how this is done? Bvic4 (talk) 17:10, 1 March 2008 (UTC)