how i can calculate roots of the characteristic polynomial equations {dsys and dsys2}
and dsolve them with arbitrary initial condition for differennt amont of m and n?
thanks
Kr.mw 
 

Download Kr.mw

Hi all,

I start working with the Grid package.
To familiarize myself with it I ran the "primeChecker" example, which of course has worked perfectly well.

Next I did this (a priori harmless) simple modifications :

1. within the primeChecker procedure :
   replace  myVal := userData[thisNode+1] :
   by         myVal := userData[thisNode+1, 1] :
2. before launching the procedure with Grid[Launch] :
   replace  userData := [ .... ] :  #which is a list
   by         userData := [ .... ] :  # the same thing
                userData := convert(userData, matrix): 

I get the following error message :
error, (in unknown) Matrix index out of range

What does it mean and how can I fix this ?

Thanks in advance

I have problem to get real answer in a simple equation. maple just give me complex answer.

how i can get parametric real answer? Ihave trid this two way but not applicaple.

with(RealDomain); assume(T::real)

My code is:
Qz := 7.39833755306637215940309264474*10^7*sqrt(1/T)*(T-297.2)/T-16242.7935852035929839431551189*sqrt(1/T)/T;

q := (.6096*(299.2-T))/(sqrt(1.60000000000000000000000000000*10^(-9)-r^2)-0.346410161513775458705489268300e-4);

with(RealDomain); assume(T::real);

e := simplify(solve({0 = q-Qz}, {T}))

and the result like:

e := {T = 1/RootOf(-609600000000000000000000000000000000000000000000000000000+(879515018020273730453559011332895956000000000000000000000000000*sqrt(-625000000*r^2+1)-761682348615485390130551939524898425387968750740910059296172487)*Z^5+(-2959335021226548863761237057896000000000000000000000000000000*sqrt(-625000000*r^2+1)+2562859306691152293409465394507279449380503585614734443742000)*_Z^3+182392320000000000000000000000000000000000000000000000000000*_Z^2)^2}

dose anyone hase any opinion?

Hello

I have experienced that maple does not save all of the varibles. But some it does.

I calculate with units, could that be the reason?

I have allso been thinking that it has something to do with saving the document online in onenote. But that works like the file is saved on the Pc's harddrive.

Are there anybody else that has experienced this?

I calculate with units, but as the varible does not appear in the calculation with units, I make one varible with the same result, to get the next calculation to work.   

Regards

Heide

Does `evala/toprof` still exist in newer Maple versions, or is there an equivalent?

Why won't this procedure Compile? All I get is a cryptic and ungrammatical error message.

    step:= proc(
          n::integer[4],
          XYZ::Matrix(datatype= float[8]),
          E::Vector(datatype=integer[4]), F::Vector(datatype=integer[4]),
          W::Matrix(datatype= float[8]), #3x2 scratch matrix
          mu::integer[4]
     )
     option autocompile;
     local
          i::integer[4], j::integer[4],
          ed::float[8],
          fd::float[8],
          p::float[8], t::float[8]       
     ;
          to mu do
               for i to n do
                    ed:= 0;  fd:= 0;
                    for j to 3 do
                          p:= XYZ[i,j];
                          t:= XYZ[E[i],j] - p;
                          ed:= ed+t^2;
                          W[j,1]:= t;
                          t:= XYZ[F[i],j] - p;
                          fd:= fd+t^2;
                          W[j,2]:= t
                    od;
                    ed:= sqrt(ed) + .01;  fd:= sqrt(fd) + .01;
                    for j to 3 do
                         XYZ[i,j]:= 0.995*XYZ[i,j] - 0.01*W[j,1]/ed + 0.02*W[j,2]/fd
                    od
               od
          od
     end proc;
Compiler:-Compile(step);

Error, (in Compiler:-Compile1) In memory compilation failed

Dear all,

I have somme difficulties to calculate this integral.

int(I*sqrt((R*exp(I*theta)+1)/(R*exp(I*theta)-a)), theta = 0 .. Pi);

Thanks

Hello guys,

I was just playing around with differential equations, when I noticed that symbolic solution is  different from the numerical.What is the reason for this strange behavior?

ODE := (diff(y(x), x))*(ln(y(x))+x) = 1

sol := dsolve({ODE, y(1) = 1}, y(x))

a := plot(op(2, sol), x = .75 .. 2, color = "Red");
sol2 := dsolve([ODE, y(1) = 1], numeric, range = .75 .. 2);

with(plots);
b := odeplot(sol2, .75 .. 2, thickness = 4);
display({a, b});

Strange_issue.mw

Mariusz Iwaniuk

Hello,

I need to crate a function to be evaluated in a range of values, and this function i would to use in other expression, example:

cel1      "seq(i,i=0.001..2,0.001)"

cel2      "A:=&1";cel1

cel3      "f:=x->diff(KelvinBei(0,x),x)"

cel4      ""B:=map(x->f(x),[A])"

This is ok with a lot of function but with diff(KelvinBei(0,x),x) in cel4 show this error "Error,(in f) invalid input:.1e-2, which is not valid for its 2nd argument.

Why??? How can I do??

Hello guys,

I was just playing around with the Shanks transformation of a power series, when I noticed that polynomials aren't evaluated as I would expect.
I created this minimal working example; the function s should evaluate for z=0 to a[0], however it return simply 0.
Is there something I messed up?

Download evaluate_sum.mw

Thanks for your help,

Sören

Hi all,

It is believeble for me that the KummerU function is infinite or has a singular solution at r=0;

but without the command D(R) and dsolve ({er, D(R)(0)=0}, {R(r)}) that show the r=0 is a singular solution for the R(r), how could I prove it without using of these commands: for example is plotting of this function applicable??

while we have not the value of the  \lambda

Download Kummer.mwKummer.mw

Hi all,

I am generating a sphere with increasing radius that interacts at some point with a plan, just like this:

I would like to find a way to make the sphere "wave" (I agree this is not a wave...) reflected by the plan as in a mirror.

How could I do that ?

Thanks a lot for your help.

B

Im trying to draw a shpere but it always saying: 

Error, (in plot3d) unexpected option: z = -2 .. 2

this is the equation: x^2+y^2+z^2-4=0

i'm writing this way

plot3d(x^2+y^2+z^2-2^2, x = -2 .. 2, y = -2 .. 2, z = -2 .. 2)

what should I do? this is my first time with this software

best from Brazil,
Nina

Greetings to all.

With the following matter I am betting on there being a simple mistake on my part due to fatigue owing to a challenging session of intense computing. The following link at Math.Stackexchange.Com points to a computation involving complex residues. Consult the link for additional details.

I usually verify my computations with Maple, I did the same this time. Thereby I happened on a curious phenomenon which I have documented below. Please study the session data provided, I believe it speaks for itself.

user@host:~$ math
Mathematica 10.0 for Linux x86 (64-bit)
Copyright 1988-2014 Wolfram Research, Inc.

In[1]:= Residue[z^2/(z^4 + 2*z^2 + 2)^2, {z, 2^(1/4)*Exp[3*Pi*I/8]}]

            1/8      1/4
        (-1)    ((-1)    + Sqrt[2])
Out[1]= ----------------------------
            1/4      1/4           3
        16 2    ((-1)    - Sqrt[2])

In[2]:= N[%]

Out[2]= 0.117223 - 0.0083308 I

In[3]:=
user@host:~$ maple
    |\^/|     Maple 18 (X86 64 LINUX)
._|\|   |/|_. Copyright (c) Maplesoft, a division of Waterloo Maple Inc. 2014
 \  MAPLE  /  All rights reserved. Maple is a trademark of
 <____ ____>  Waterloo Maple Inc.
      |       Type ? for help.
> residue(z^2/(z^4 + 2*z^2 + 2)^2, z=2^(1/4)*exp(3*Pi*I/8));
                                       0

> quit
memory used=0.9MB, alloc=8.3MB, time=0.07
user@host:~$

I am looking forward to learning what the correct syntax is to get the residue in this case and I hope I can assist other users who might have run into the same problem. I will cancel the question should it turn out to be trivial and of little potential use to the community.

Best regards,

Marko Riedel

Post Scriptum. Being a programmer myself I would be curious to learn more about the algorithms that are deployed here and how and why they did not succeed.

Please check this:

N:=3;

sum1 := lcm(N, 0)+lcm(N, 1)+lcm(N, 2)+lcm(N, 3);

sum2 := sum(lcm(N, k), k = 0 .. N);

Why is sum2 wrong?

Regards,

César Lozada