@Al86 The u example that I used satisfies that PDE, so the identity still doesn't hold.

@Kitonum It means the same thing as does NaN (Not a Number) in the IEEE 754 standard for (double-precision) floating-point arithmetic that Maple uses. See the Wikipedia page on NaN. In this case, I suspect that it comes from computing the difference of two very large positive numbers whose difference is very small. If you increase Digits to 15, the problem will go away.

@ 

Changing int to Int should substantially reduce the computation time. I don't have time to test it right now. As it is, it is attempting a symbolic integration every time YFD is called with numeric input.

@Markiyan Hirnyk Replace your map with map[inplace, evalhf] and you should get about a factor-of-10 time reduction.

@tomleslie 

• Yes, I meant assign (original Answer corrected).
• Yes, AFAIK, all of Maple's solving commands treat algebraic expressions as equations equated to 0.
  
• The process you describe is esentially equivalent to using eliminate, where one can clearly see that the reduced equations (the second returned set) are inconsistent.

@Bendesarts The embedded semicolons make this problem more difficult than something that can be handled with some simple StringTools commands. Maple does have it's own Matlab-to-Maple translator: Matlab:-FromMFile (see ?Matlab,FromMFile). It does have some limitations on the complexity of the Matlab code that it can handle, but I think that it can handle what you've presented above. 

I believe that the embedded prompt (>) symbols on copy-and-paste are due to a bug in Maple 2015 that's already been corrected in Maple 2015.1. I'm not sure about that. Hopefully someone else here will comment on that. It that's not the problem, I can come up with a StringTools solution for that problem.

@erik10 Adding an icosahedrom wireframe is much easier than your Reply suggests. Starting with Kitonum's PlotFootball, do

FB:= PlotFootball([red,yellow]);
plots:-display(
     FB,
     geom3d:-draw(geom3d:-icosahedron(Icosa, C, 1.2), style= wireframe, thickness= 4)
);

@tomleslie There is a worksheet link at the bottom of the Question, and it's been there since the Question was first posted.

@Markiyan Hirnyk Even plots is not needed for this.

restart:
with(geom3d):
draw(TruncatedIcosahedron(football, point(C,(0,0,0)), 1));

@acer Can I take your lack of mention of my reformulation of the Question to mean that, as far as you know, it isn't possible to use external files with Maple Player?

@tomleslie Oh, I forgot to say that I applied simplify to the integrand. Sorry about that. I updated my Reply. So, using your formulation,

int(simplify(expr), z= 0..infinity);

@tomleslie Thank you for your response to my Question. Yes, &under is obscure and difficult to look up in the help. It's documented at ?type,structured in the last paragraph of Description and the last four Examples. Its action is completely controlled by the easy-to-understand one-line procedure `type/&under`. Your guess as to its meaning was spot on. Unfortunately, your proposed workaround doesn't help me because I need the expressions as they are before they are converted.

I think that &under is only tangentially related to the cause of the problem. I say that because if I execute trace(`type/&under`) before making the erroneous indets call, I see that the procedure is never called for the missing derivative. Preben's and Acer's analyses make me think that the error is more closely related to the convert.

First, you have an extra z between the integrand and the interval of integration. Get rid of that.

If I assume that all parameters are positive, apply simplify to the integrand, and make the interval 1..infinity or 0..infinity, then Maple does the integration. But, if I also assume that y/A[o]^2 > 1 and keep the interval as y/A[o]^2..infinity, it remains unevaluated. I don't know why it can do one and not the other. 

Your title says "integration from zero to infinity" but your code has y/A[o]^2 to infinity. Which is correct?

LinearAlgebra is completely irrelevant to this Question. You shouldn't clutter your Question and your code with irrelevant and potentially confounding things.

@tomleslie 

To be more pedantic, you're ignoring the commas in Acer's comments, which indicate that he is not saying that the PDF version is included in Maple. He's saying that the given hyperlinks point to PDF versions of the same texts which are included with Maple in a different format.

It is a good question, but the salient detail is how to use an .mla archive (or any external code or data file) in Maple Player. Surely it makes no difference whether the code is in the form of a module or any other programming structure.