## 432 Reputation

15 years, 154 days

## An issue here is the meaning...

An issue here is the meaning of “rational”. In Maple, the term refers to a data type; in mathematics, it refers to a particular (different) set. Using the Maple definition, `is(3.14,'rational')` should (and does) return false. Returning true would require using the mathematical definition. When Maple and mathematics use the same term with different meanings, things often become problematic. So I think that Maple should avoid doing that. I.e. I think that Maple should only use a mathematical term if the term has essentially the same meaning as it does in mathematics (as close as a computer implementation feasibly allows). Use of the term “rational” for the data type is thus questionable. This is essentially the same point that Dave L and I discussed, only there the term was “set” and the issue was having Maple sets be defined with an order (and so different from mathematical sets). If Maple needs a term for a data type, pick a non-mathematical term specifically for that. E.g. “float” works fine. And if Maple is to have ordered sets, call them “osets”, or “ulists” [unique-element lists], or something, but not “sets”.

## An issue here is the meaning...

An issue here is the meaning of “rational”. In Maple, the term refers to a data type; in mathematics, it refers to a particular (different) set. Using the Maple definition, `is(3.14,'rational')` should (and does) return false. Returning true would require using the mathematical definition. When Maple and mathematics use the same term with different meanings, things often become problematic. So I think that Maple should avoid doing that. I.e. I think that Maple should only use a mathematical term if the term has essentially the same meaning as it does in mathematics (as close as a computer implementation feasibly allows). Use of the term “rational” for the data type is thus questionable. This is essentially the same point that Dave L and I discussed, only there the term was “set” and the issue was having Maple sets be defined with an order (and so different from mathematical sets). If Maple needs a term for a data type, pick a non-mathematical term specifically for that. E.g. “float” works fine. And if Maple is to have ordered sets, call them “osets”, or “ulists” [unique-element lists], or something, but not “sets”.

## Maple can...

`Q:= x-> piecewise(type(x,rational), 1, 0);` int(Q(x), x = 0 .. 1)           0

## Maple can...

`Q:= x-> piecewise(type(x,rational), 1, 0);` int(Q(x), x = 0 .. 1)           0

## Maple 11.01 versions...

The Maple 11.01 kernel has build #296069. There was a later build of the user interface only (#303882). For details, see this thread.

## whattype...

That sounds like a bug. Has it been reported/documented?

## whattype...

That sounds like a bug. Has it been reported/documented?

## New MaplePrimes layout...

I like having the new Student section. Regarding the layout, how about if the Announcements section, currently at top right, was moved to be on the left, either above or below the Navigation section?

## animate background...

Okay, go into the Help system, and where it says “Search For:”, click on Text (the default is Topic). Then enter “background animate” in the search box (without the quotes). That should bring up a Help page that discusses the `background` option of the `animate` command. An alternative method is given on the first Help page found by text-searching for “background plots”.

## animate background...

Okay, go into the Help system, and where it says “Search For:”, click on Text (the default is Topic). Then enter “background animate” in the search box (without the quotes). That should bring up a Help page that discusses the `background` option of the `animate` command. An alternative method is given on the first Help page found by text-searching for “background plots”.

Ahhh, I misread the plot, of course. No fault of Maple's.

## consistency with sqrt over reals...

The equation can be plotted. `plots:-animate3d(eqn, a=-2..2, b=-2..2, c=-2..2, axes=framed, frames=21)` Doing that helps to visualize how the only real solution is 0. Yet `use RealDomain in solve(eqn, c) end use` claims that  (b^2+a^2)/(a^2+1)  is also a solution in the reals. So how are animate3d and RealDomain:-solve consistent?

## MeijerG simplifications...

(Scott, I get the same behavior as Andrew, using Maple 11.01.) Andrew, Maple and Mathematica each have strengths and weaknesses relative to the other. In this case, it seems that Maple does not simplify the constant   MeijerG([[1, 1], ], [[1, 1/2, 1/2], []], 1)  to  4*Pi. It might be relevant that no identities for the MeijerG function are known to Maple (according to FunctionAdvisor).

## NAG?...

Could NAG routines be used?

## NAG?...

Could NAG routines be used?
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