@nm The OP means Pi = sum(..., n= 0..infinity).

@Kitonum You could also replace `` with ` ` and thus maintain the intended blank-line appearence.

This must be considered a bug as `` is common in Maple code, especially as a function.

With that combination of keystrokes, nothing special happens for me. I'm on Windows 8, Maple 17.02/64, Standard GUI.

@J4James You can also use dsolve option method= classical[rk4].

@emmantop Okay, we need a specific numeric value for parameter k_1.

Your code has a variable with no specified value: zeros. Is this something that you assigned earlier? Could you show the plot command that you used?

@adel-00 In general, there are three values of N for each K. Finding those N involves solving a cubic equation. Here's a simple procedure to get those three values.

Nk:= unapply([solve(K(N) = Kn, N)], Kn);

@Markiyan Hirnyk I wish I could delete tags. I would delete "query".

I can't execute your code because there are five Vectors that did not get transcribed when you cut-and-pasted the code. Try setting

interface(rtablesize= infinity);

and then try the cut-and-paste again.

Also, try to upload the worksheet as an attached file. This hasn't been working very well lately, but it works sometimes.

Like I said to your earlier version of the question: Do you really want to use RK4? Is your goal to solve the ODE, or is your goal to complete a programming exercise for RK4? You will need to specify a numeric value for k_1 either way.

@Kitonum Yes, ilog10, ilog2, and length are much faster than ceil@log[10] for exact aritnmetic.

@Joe Riel The procedure has option remember, but it is not an essential part of the computation like it is with the recursive procedure.

@Andriy In your animate command, you use u(t,x). In the vast majority of cases, arguments are evaluated before they are passed.

Do you really want to use RK4? There are easier ways. To use RK4, we need to convert to a first-order system. And however it's solved, we'll need another initial condition.

@niller123 Sorry, there's currently a bug with uploading files. I'll send you an email, and you reply to it with the file.