> q := x^(1/2):

> type(q, `^`);
                                     true
> op(0,q);
                                       ^

> subsindets(q, `^`, f->subsop(0=H,f));
Error, (in unknown) improper op or subscript selector

What's wrong with that last one? It's modelled on the first Example in the ?subsindets help-page.

Are there cases where...

Hi, I am facing a problem to copy the Maple output into SWP5.0. When I paste the output, generated by 

print(expression,latex);

in SWP it remains mere ASCII. Kindly guide me. Thanx.

Maple 12, Mac OS 10.5 see "invalid character ..." messages! . . How about other platforms?

Dear all, I am working with Maple 11 and 12 on an Intel Mac running Leopard, and I am having trouble with a very simple script that keeps telling "kernel connection lost"; see below. > restart; with(CurveFitting); > poly2 := proc (x, u) return PolynomialInterpolation(x, u, z) end proc; proc(x, u) ... end; > getArrays := proc (left, right) local x, u; x := [seq(h*i, i = left .. right)]; u := [seq(u[i], i = left .. right)]; return x, u end proc; proc(left, right) ... end; > x, u := getArrays(-2, 2); [-2 h, -h, 0, h, 2 h], [u[-2], u[-1], u[0], u[1], u[2]]

Why does the following give me an imaginary number?

 (-.008)^(1/3);

In a concurrent thread I posted the following simplification procedure

  Tryhard:= proc(expr)
    global E_in_Tryhard;
    subs(pow= `^`,
      codegen[optimize](subs(E_in_Tryhard= expr, ()-> E_in_Tryhard), tryhard))()
  end proc;

and now put into an extra blog post, as it might be helpful for others. Note, that this does not work on all constructs in Maple and certainly the package is a bit dated.

I have recently wanted to work with finite groups of small order in Maple. Some other packages, such as GAP, allow one to easily work with any finite group of size up to 2000. As far as I can tell no such capability existed for maple so I have tried my hand at my first package, "tinygroups," which is basically a list of all of the nonisomorphic groups of up to 60 elements. It can be obtained here:

http://www.math.uwaterloo.ca/~dagpritc/math/tinygroups/

So what should i mod 0 really be equal to?

I understand that isolve doesn't work with inequalities, at least it is not mentioned on the isolve help page. Still, the following seems strange,

isolve({40*a+60*b<=150, a>=0, b>=0});

                             {b = _NN1~}

It is related to that post.

Alec

PS By the way, some of such problems that Maple can't solve, are not even high school problems - they are an elementary school (and maybe even kindergarten) problems. -Alec

Hi all,

I'm trying to solve linear programs on Maple 11, but it is not giving me an answer. Have I made a mistake? The comand I used is:

with(Optimization):

LPSolve(40*a + 60*b, {40*a + 60*b <= 150}, assume=nonnegint, maximize)

and maple returns:

"Warning, problem appears to be unbounded".

 

But in Maple 10, this same comand works perfect. Does someone know why Maple 11 doesn't??

Mario

I was working on this fairly short equation. The solution gives different results in Maple 11.01 and 11.02:

> solve(0.981747e-8*RR+0.16549e-34*(1/RR^3-1/(0.50e-9+RR)^3)+(0.44e-26*(1+0.127324e10*RR))*10.000^2/RR^2 = 0., RR)

The equation has 7 solutions, of which 3 are real, one of which is for example -9.959429517E-10. The correct value is negative, however Maple 11.01 (build 296069) gives 9.959429517E-10, while Maple 11.02 gives -9.959429517E-10.

I know that a computer can't generate a random number in the true sense of the word random. But I was expecting more when I went to do a rand(1..100); 5000 times and found most of the generated values to be between 1 and 10. Go ahead and give this a try:

As the discussion in this thread  did not provide me a clear understanding of the implementation and intended usage of the property 'continuous' I have looked at this subject a bit further. And as it is an underdocumented subject, it seems fit to post here some issues that I have found.

Eval help page contains the following statement:

Since eval does pointwise evaluation, eval cannot be used to evaluate an expression at a singularity. Use limit instead.

This is a serious error showing that the person writing it doesn't understand the difference between the value of a function at a point and the limit at that point.

At discontinuity, the value of a function is _not_ equal to the limit - that's why it is discontinuity. If the value of a function was equal to the limit, the function would be continuous at that point.

An example:

Hi everyone,

I am looking at the following ODE:

x'(t) + a(t)*x(t)  - t*a(t) + b*a(t)*f(x(t)) = 0

where x is the function of t to be found
with t>=0, x(t)>0
with initial condition x(0)=x0 > 0 given
with a(t) a known function of t inside the positive quadrant, a(t)>0
with f(x) a known function of x inside the positive quadrant, f(x)>0
with b a known positive real constant, b>0

If b=0, we have a first-order linear ODE, but I'm interested in b>0.