So your y1,...yn are floats? If so then what happens if you raise Digits in Maple? (Ie. to 15, and then to 30?) Numeric roundoff error can be different for different (equivalent) forms of an expression, even without the kind of algebraic cancellation that Carl described. Applying `simplify` will not necessarily reduce the numeric roundoff effects for subsequent floating-point substituion and evaluation.

Why use `subs` instead of `eval`, btw?

acer

So your y1,...yn are floats? If so then what happens if you raise Digits in Maple? (Ie. to 15, and then to 30?) Numeric roundoff error can be different for different (equivalent) forms of an expression, even without the kind of algebraic cancellation that Carl described. Applying `simplify` will not necessarily reduce the numeric roundoff effects for subsequent floating-point substituion and evaluation.

Why use `subs` instead of `eval`, btw?

acer

@Carl Love Using your code above I get,

  > about(x1);

Originally x, renamed x~:
  is assumed to be: RealRange(Open(1),infinity)

even after the additional qualification `x>2` is made.

I get that in Maple 11 through 17, on Windows.

Above your results show,

  > about(x1);

Originally x, renamed x~:
  is assumed to be: RealRange(Open(2),infinity)

which I don't obtain.

@Carl Love Using your code above I get,

  > about(x1);

Originally x, renamed x~:
  is assumed to be: RealRange(Open(1),infinity)

even after the additional qualification `x>2` is made.

I get that in Maple 11 through 17, on Windows.

Above your results show,

  > about(x1);

Originally x, renamed x~:
  is assumed to be: RealRange(Open(2),infinity)

which I don't obtain.

Is your acquaintance running 32bit or 64bit Maple on Windows?

acer

@Carl Love Carl, you wrote in a Comment above that, "Most interesting is that all copies end up with the same assumptions."

In which version did you obtain those results from the `about` command, may I ask?

@Carl Love Carl, you wrote in a Comment above that, "Most interesting is that all copies end up with the same assumptions."

In which version did you obtain those results from the `about` command, may I ask?

@emma hassan Well, you already have a table, as V;

eval(V);

If you want you can turn V into a Matrix (and then right-click and browse as one way to view its entries), or call plots:-surfdata on that.

matdata:=Matrix(M,N,V);

plots:-surfdata(matdata,axes=box);

@emma hassan Well, you already have a table, as V;

eval(V);

If you want you can turn V into a Matrix (and then right-click and browse as one way to view its entries), or call plots:-surfdata on that.

matdata:=Matrix(M,N,V);

plots:-surfdata(matdata,axes=box);

Are a,b,c,... each something numeric? Are F1 and F2 numeric? Are they floating-point?

acer

@Carl Love I had written an explanation of what my answer was supposed to convey, but lost it entirely when hitting the Submit button (the site game me that new message about there being a problem with the submission...). No back action available in my chrome tag. Extreme wtf moment.

Anyway, my earlier intention was to wait until finding out something more about the OP's motivation in asking why it didn't "work" before spending time fiddling with evalf[d] or ilog10 (or what have you) to accomodate the region about zero. But being unable to use the site's editor as usual made me lose interest.

@Carl Love I had written an explanation of what my answer was supposed to convey, but lost it entirely when hitting the Submit button (the site game me that new message about there being a problem with the submission...). No back action available in my chrome tag. Extreme wtf moment.

Anyway, my earlier intention was to wait until finding out something more about the OP's motivation in asking why it didn't "work" before spending time fiddling with evalf[d] or ilog10 (or what have you) to accomodate the region about zero. But being unable to use the site's editor as usual made me lose interest.

@bryon I tried to edit an exisiting Answer of mine (after the first fix), and the HTML mode of the editor showed only as blank. The content was not avaiulable for editing.

@Markiyan Hirnyk Thanks, I was having a lot of trouble editing my answer, trying to add in the plots.

It is not completely clear (to me) exactly what the Asker wants to obtain, in terms of a visual result.

@Markiyan Hirnyk Thanks, I was having a lot of trouble editing my answer, trying to add in the plots.

It is not completely clear (to me) exactly what the Asker wants to obtain, in terms of a visual result.