DJKeenan

432 Reputation

9 Badges

15 years, 265 days

MaplePrimes Activity


These are replies submitted by DJKeenan

I just tried process[launch]("C:/WINDOWS/system32/notepad.exe"); in standard Maple 11.01, running under Windows XP (SP2). It worked fine.
I just tried process[launch]("C:/WINDOWS/system32/notepad.exe"); in standard Maple 11.01, running under Windows XP (SP2). It worked fine.
Thanks for pointing this out. In the example you give, I get two of the roots (using Maple 11.01), but not the third. restart; with(RealDomain): solve(x^3-3*x+1 = 0);        -cos((2/9)*Pi)-sin((2/9)*Pi)*3^(1/2), -cos((2/9)*Pi)+sin((2/9)*Pi)*3^(1/2) Apparently Maple is not determining that the other root is real. restart; s:=solve(x^3-3*x+1 = 0): seq(is(simplify(i), 'real'), i = s);       FAIL, true, true I think that Maple should be able to determine realness in this example. In general it cannot be done, though, but I would expect Maple to then issue a warning and set _SolutionsMayBeLost. I.e. I would consider this a bug.
Thanks for pointing this out. In the example you give, I get two of the roots (using Maple 11.01), but not the third. restart; with(RealDomain): solve(x^3-3*x+1 = 0);        -cos((2/9)*Pi)-sin((2/9)*Pi)*3^(1/2), -cos((2/9)*Pi)+sin((2/9)*Pi)*3^(1/2) Apparently Maple is not determining that the other root is real. restart; s:=solve(x^3-3*x+1 = 0): seq(is(simplify(i), 'real'), i = s);       FAIL, true, true I think that Maple should be able to determine realness in this example. In general it cannot be done, though, but I would expect Maple to then issue a warning and set _SolutionsMayBeLost. I.e. I would consider this a bug.
That makes sense. Kind thanks for explaining.
You might look at surd. surd(-1,5);               -1 An odd surd of a negative real is real.
You might look at surd. surd(-1,5);               -1 An odd surd of a negative real is real.
Another approach is this. alf:=$"a".."z": H:= n-> add(convert(alf[k+1],'name')*x^k, k=0..n); Alternatively, you might use constants c0,c1,...,cn, perhaps with the indices subscripted. K:= n-> add(cat('c',k)*x^k, k=0..n); J:= n-> add('c'[k]*x^k, k=0..n);
According to ISO 31-11, it should be <r,phi,theta>. So VectorCalculus is consistent with that. The <r,theta,phi> format dates from older parts of Maple (and I suspect that that format was the more common one at the time).
According to ISO 31-11, it should be <r,phi,theta>. So VectorCalculus is consistent with that. The <r,theta,phi> format dates from older parts of Maple (and I suspect that that format was the more common one at the time).
Here is the correct link to the new podcast: http://www.maplesoft.com/community/podcast/view.aspx?SID=5187
Jacques, thanks!
Jacques, thanks!
The issue is 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). In Maple, irrational is not defined as the logical negation of rational. For example is(0., 'rational')        false is(0., 'irrational')        FAIL In Maple, irrational seems to be consistently defined as in mathematics (to the extent feasible). I think that that is the right approach. The definition of rational is questionable, as I said. In fact, there appears to be more than one definition, as JacquesC indicated. type(gamma, 'rational')        false is(gamma, 'rational')        FAIL (Although quick google shows that a proof of irrationality was claimed in 2003.) Separately, why should int(QBar(x),x=0..1.5) evaluate to 1? QBar is 1 almost everywhere.
The issue is 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). In Maple, irrational is not defined as the logical negation of rational. For example is(0., 'rational')        false is(0., 'irrational')        FAIL In Maple, irrational seems to be consistently defined as in mathematics (to the extent feasible). I think that that is the right approach. The definition of rational is questionable, as I said. In fact, there appears to be more than one definition, as JacquesC indicated. type(gamma, 'rational')        false is(gamma, 'rational')        FAIL (Although quick google shows that a proof of irrationality was claimed in 2003.) Separately, why should int(QBar(x),x=0..1.5) evaluate to 1? QBar is 1 almost everywhere.
5 6 7 8 9 10 11 Page 7 of 13