Hello,

I'm trying to solve a differential equation with boundary conditions using dsolve. However dsolve return nothing. Any help to understand what's happening?

Thank you!

Here's my code:

eq1:=diff(psi(s),s,s)=t*sin(psi(s))-r*cos(psi(s));
eq2:=diff(x(s),s)=cos(psi(s));
eq3:=diff(y(s),s)=sin(psi(s));

cond1:=x(0)=0;
cond2:=x(1)=d+1;
cond3:=y(0)=0;
cond4:=psi(0)=0;
cond5:=D(psi)(0)=0;
cond6:= y(1)=0;

dsolve({eq1,eq2,eq3,cond1,cond2,cond3,cond4,cond5,cond6});
 

Dear all

I  compute the radius of convergence of power series using maple, 

but the code does not give any result

radius_convergence_PSeries.mw

thank you for any help 

This worksheet animates part of the motion of the classic ladder sliding down a wall.

Please answer the two questions posed in the opening text.

Respondents will need to establish their own link to the DirectSearch package

Slide_Ladder.mw

Hi, I am very new in maple. I want to create a list of 54 quartic polynomials f=x^4 + a_3*x^3 + a_2*x^2 + a_1*x + a_0 with coefficients 0<=a_i<=2 and a_0 <> 0 . 

f := x ->  x^4 + add(a[i]*x^i, i = 0 .. 3);
for m to 54 do
    pol[m] := f(x);
end do;

How do I incorporate conditions 0<=a_i<=2 and a_0 <> 0 into this cycle so I can get 54 different combinations of coefficients? Thank you.

restart;
u := (H(x, t, z)+sqrt(R))*exp(I*R*x);
                /              (1/2)\           
                \H(x, t, z) + R     / exp(I R x)

I*(Diff(u, z))+Diff(u, `$`(x, 2))+Diff(u, `$`(t, 2))+(abs(u)*abs(u))*u-((abs(u)*abs(u))*abs(u)*abs(u))*u;
  / d  //              (1/2)\           \\
I |--- \\H(x, t, z) + R     / exp(I R x)/|
  \ dz                                   /

     / 2                                   \
     |d  //              (1/2)\           \|
   + |-- \\H(x, t, z) + R     / exp(I R x)/|
     \                                     /

     / 2                                   \                    
     |d  //              (1/2)\           \|                  2 
   + |-- \\H(x, t, z) + R     / exp(I R x)/| + (exp(-Im(R x)))  
     \                                     /                    

                       2                                    
  |              (1/2)|  /              (1/2)\              
  |H(x, t, z) + R     |  \H(x, t, z) + R     / exp(I R x) - 

                                        4                       
                 4 |              (1/2)|  /              (1/2)\ 
  (exp(-Im(R x)))  |H(x, t, z) + R     |  \H(x, t, z) + R     / 

  exp(I R x)
value(%);
  / d            \              / d  / d            \\           
I |--- H(x, t, z)| exp(I R x) + |--- |--- H(x, t, z)|| exp(I R x)
  \ dz           /              \ dx \ dx           //           

         / d            \             
   + 2 I |--- H(x, t, z)| R exp(I R x)
         \ dx           /             

     /              (1/2)\  2           
   - \H(x, t, z) + R     / R  exp(I R x)

     / d  / d            \\                             2 
   + |--- |--- H(x, t, z)|| exp(I R x) + (exp(-Im(R x)))  
     \ dt \ dt           //                               

                       2                                    
  |              (1/2)|  /              (1/2)\              
  |H(x, t, z) + R     |  \H(x, t, z) + R     / exp(I R x) - 

                                        4                       
                 4 |              (1/2)|  /              (1/2)\ 
  (exp(-Im(R x)))  |H(x, t, z) + R     |  \H(x, t, z) + R     / 

  exp(I R x)
simplify(%);
  / d            \              / d  / d            \\           
I |--- H(x, t, z)| exp(I R x) + |--- |--- H(x, t, z)|| exp(I R x)
  \ dz           /              \ dx \ dx           //           

         / d            \                 2                      
   + 2 I |--- H(x, t, z)| R exp(I R x) - R  exp(I R x) H(x, t, z)
         \ dx           /                                        

      (5/2)              / d  / d            \\           
   - R      exp(I R x) + |--- |--- H(x, t, z)|| exp(I R x)
                         \ dt \ dt           //           

                                                  2           
                             |              (1/2)|            
   + exp(-2 Im(R x) + I R x) |H(x, t, z) + R     |  H(x, t, z)

                                                  2       
                             |              (1/2)|   (1/2)
   + exp(-2 Im(R x) + I R x) |H(x, t, z) + R     |  R     

                                                  4           
                             |              (1/2)|            
   - exp(-4 Im(R x) + I R x) |H(x, t, z) + R     |  H(x, t, z)

                                                  4       
                             |              (1/2)|   (1/2)
   - exp(-4 Im(R x) + I R x) |H(x, t, z) + R     |  R     
collect(%, exp(I*R*x));
 /  (5/2)       / d            \      2           
 |-R      + 2 I |--- H(x, t, z)| R - R  H(x, t, z)
 \              \ dx           /                  

        / d            \   / d  / d            \\
    + I |--- H(x, t, z)| + |--- |--- H(x, t, z)||
        \ dz           /   \ dx \ dx           //

      / d  / d            \\\           
    + |--- |--- H(x, t, z)||| exp(I R x)
      \ dt \ dt           ///           

                                                   2           
                              |              (1/2)|            
    + exp(-2 Im(R x) + I R x) |H(x, t, z) + R     |  H(x, t, z)

                                                   2       
                              |              (1/2)|   (1/2)
    + exp(-2 Im(R x) + I R x) |H(x, t, z) + R     |  R     

                                                   4           
                              |              (1/2)|            
    - exp(-4 Im(R x) + I R x) |H(x, t, z) + R     |  H(x, t, z)

                                                   4       
                              |              (1/2)|   (1/2)
    - exp(-4 Im(R x) + I R x) |H(x, t, z) + R     |  R     
 

restart;
H := a__1*exp(I*(-Omega*t+k*x+z*k[1]))+a__2*exp(-I*(-Omega*t+k*x+z*k[1]));
I*(diff(H, z))+diff(H, x, x)+diff(H, t, t)+R*(H+conjugate(H))+R^2*(H+conjugate(H))*H;
value(%);
simplify(%);

Download m18bs.mw

Hi,

I'm trying to solve the attached system but I don't know how to proceed.

Any ideas?

Thanks very much in advance.

Best regards,

Download maple_problem.mw

I run Maple 2021 under Ubuntu 20.04 on a new Lenovo laptop with 32Gb of Ram. Every time I start Maple, it runs for a few minutes and then loses the "kernel connection". I have to save the worksheet and re-start Maple. In dmesg, I find:

[ 1436.724570] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/user.slice/user-1000.slice/user@1000.service,task=mserver,pid=8037,uid=1000
[ 1436.724589] Out of memory: Killed process 8037 (mserver) total-vm:31723552kB, anon-rss:31289772kB, file-rss:60kB, shmem-rss:0kB, UID:1000 pgtables:61656kB oom_score_adj:0
[ 1437.151441] oom_reaper: reaped process 8037 (mserver), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

indicating that Maple's virtual memory exceeded 30 Gb! This happens even if the only command I execute is, for instance, "resrart" or "A:=1" and nothing else. It also happens when no other applications are running and the "top" command indicates that around 30Gb of RAM is available.

In this state, Maple is utterly useless to me. This was a new install of Maple and a fresh install of Ubuntu on a new laptop, surely I am not the only one seeing this?

I have tried setting a 30Gb limit in "kerneloptions" for "stacklimit" but that di not make a difference.

If you have seen any behaviour like this, please respond. Is there some bug in Maple that leads to oncontrolled and unprovoked memory grabbing?

I am attempting to add the contents of a variable based on the contents of another. There should be some way to do this without looping. I get errors when trying to do this with seq. I seem to not understand evaluation...

How do I do this?

restart;
## generate some values like in the real app
roll:=rand(1..9):
N := sort([seq(seq(10*(2+jdx)+roll(),jdx=1..5),idx=1..10)]):
V := 10*seq(roll()+10*trunc(N[idx]/10),idx=1..nops(N)):

## generate index for sum. This groups the values for sum
sumidx := [seq(floor(N[idx]/10)-2,idx=1..nops(N))];

## create and zero sum variable
S := 0 *~convert(convert(trunc~(N/10),set),list);

## calc sum and display it - This works
for idx to nops(sumidx) do
    S[ sumidx[idx] ] += V[idx]:
end do:
S;

## error because sumidx[idx] is not evaluated ?????
S := 0 *~convert(convert(trunc~(N/10),set),list):
seq('S'[ sumidx[idx] ] += V[idx], idx=1..nops(N));
S;

## This works 'S' delays evaluation and sumidx[idx] is evaluated in
## the function call
f := proc( A, B )
    A += B:
end proc:
## zero sum variable
S := 0 *~convert(convert(trunc~(N/10),set),list):
seq(f('S'[ sumidx[idx] ], V[idx]),idx=1..nops(N)):
S;
 

Hello all,

I am considering the function 

I am also considering the tangent plane  at point (11,-12).

I would like to draw a 3Dplot in maple that shows the tangentplane touching the graph of f(t,u) at point (11,-12). 

I have typed the following :
 

plot3d([exp(t^2 + 10*u - 1), -121 + 22*t + 10*u], t = -1 .. 1, u = -0.7 .. 0.7, color = [red, green])
 

The 3Dplot is not correct. I have spent much time getting it to work. Could someone please assist me?

Thanks.

I can export a worksheet (to many different formats), but the normal way of doing this requires a human in the loop and several mouse operations.

Is there a way to automate this?

I have on the order of 100 different worksheets and would like to capture them in an archival format (e.g., PDF).

battery_charging_circuit.msim

I am trying to design a charge circuit for Li battery, but i don't think it is a good idea to discharge the battery by a resistor or a cuurent source. So, how can i set the parameters to make the battery discharged initially?

I am trying to find the minimum of a function TF defined by a procedure over an interval. The function depends on variable x and fixed parameters x0, L, k, alpha_0, alpha_L. Here is the function

TF := proc(x, x0, L, k, alpha_0, alpha_L) if x0 <= x then evalc(abs(cos(k*(x - L) - alpha_L)*cos(k*x0 + alpha_0)/(cos(alpha_L)*cos(k*x0 + alpha_0)))); else evalc(abs(cos(k*(x0 - L) - alpha_L)*cos(k*x + alpha_0)/(cos(alpha_L)*cos(k*x0 + alpha_0)))); end if; end proc;

When I use

Minimize('TF'(x, 0, 0.03, 55.11566060, Pi/2, Pi/4), x = 0 .. 0.03);

I get an error "Error, (in Optimization:-NLPSolve) cannot determine if this expression is true or false: 0 <= x". What is my mistake ?

Thanks.

> with(LinearAlgebra) :
> a:=<<.1,.2>|<.3,.4>>:
> ScalarMultiply(a,.1);

INTEL MKL ERROR: /home/jet08013/maple2022/bin.X86_64_LINUX/libmkl_gf_lp64.so: undefined symbol: mkl_blas_cdgmm_batch_strided.
Intel MKL FATAL ERROR: Cannot load libmkl_gf_lp64.so.
maple: fatal error, lost connection to kernel

This is EXTREMELY inconvenient.