## deleting mapleprime account...

I have multiple accounts. I would like to delete them. Please tell me how to delete it. Thank you.

## Simple non-commutative Differential Operator...

I'm using the differential operator D to differentiate variables and look at the structure of the equations, i.e. turn things like

D[1]u-vt+v^2=0 into

D[1,2](u)-D[2](v)*t+v*D[1](t)+2*v*D[2](v)=0

However, it is assumed that this is a commutative operator, i.e. D[1,2]=D[2,1]. Can I use an option to have it not commute, or should I look into using the DETools package?

Thanks,

Mike

## How calculate the Skyrme of motion from the Lagran...

How can I calculate the Euler-Lagrange equation from the Lagrangian density from Gauged Baby Skyrme model in maple using the physics package? Here, the rules of the operation in the inner space are the same that of the vectors conventional: dot and cross products, etc...
Following below the Lagrangian density.

Errata:

## Error, (in simplify/power) unable to evaluate sign...

If I used factor, it didn't simplify to 0. As you may notice that this value should be 0.

Hello,

every time I input a formula I get:

Typesetting:-mparsed(x^2 +5 -2,x^2+3; "_noterminate")

I can't get rid of this error: this is very basic, what happened?

TIA, Roberto

## sqrt output sqrt(2) in numerator...

I think   looks much nicer than

it is indeed the answer to .  Both above are equal but there are less terms on the left.  It's just what Maple does - it doesn't like radicals in the denominator.  For just a little overhead I would prefer a collection of any sqrt value into the denominator than to have to split it up.  Maybe just my preference.  Perhaps an option could be available within the Maple system to allow numeric radicals in the denominator?

## Sockets package issues - Serial interfacing ...

I get the following errors when attempting to use the Sockets package to interface with the serial input and output for a USB device connected and reported to have no known problems by Windows 10:

with(Sockets):
LookupService("busboy");
Error, could not determine determine port number for service "busboy"

LookupService(998);

Errror, cannot  determine "tcp"  service on port 998

server :=
proc (sid)
Sockets:-Write(sid, sprintf("Hello %s on port %d, from %s\r\n", Sockets:-GetPeerHost(sid), Sockets:-GetPeerPort(sid), Sockets:-GetHostName()))
end proc;

Sockets:-Serve(GetPeerPort(sid), server);

Error, (in Sockets:-GetPeerHost) Unknown error

sid := Open("localhost", "echo");

Sockets:-Serve(GetPeerPort(sid), server);

Error, (in Sockets:-Serve) cannot bind address: Unknown error

## Solving the following PDE...

How can we solve the following pde by Maple?

where v is velocity, v with dot is acceleration. (So, I think we will assume that acceleration is fixed.) And \delta is Dirac distribution.  E,I,m, M , g are fixed numbers.

Boundary conditions are:

Initial conditions are:

You can find the equation in the code: question.mw

## Corrupted file ...

Hi

I have a problem with my maple.

corrupt file

Is there anybody who can help me solve this problem.

Casper

## how i can Substituting......

i want to gain diff(p(t), t) and diff(q(t), t) and Jacobian matrix
according to the attached pdf file.

thanks

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## How do I run coding with goto on Maple? ...

Hi, I'm using Maple 2018 and I tried to run coding from https://www.maplesoft.com/applications/view.aspx?sid=4194&view=html

however, it said : unable to parse. I figured out that the problem maybe is in the if loop. though it seems perfectly fine, but it has some goto commands that i cannot search on maple website. does this mean that the goto cannot be used here and should be replaced? if yes, then how?

i am still learning on how to use maple. any help would be much appreciated. thank you!

this is the coding for if loop:

label_7;

rv:=vector([p1(x1pt,x2pt),p2(x1pt,x2pt)]):

numgeval:=numgeval+1;

printf("%5d (%8.4f,%8.4f)",numIter,rv[1],rv[2]);

max:=n;

mg:=convert(sqrt(dotprod(rv,rv)),float);

printf("%12.4f",mg);

if(mg<tol or numIter>=max) then

goto(label_6);

else

numIter:=numIter+1;

fi;

v1:=x1pt+t*rv[1];

v2:=x2pt+t*rv[2];

newt:=evalf(subs({x1=v1,x2=v2},f1));

numfeval:=numfeval+1;

lam:=fsolve(diff(newt,t)=0,t,maxsols=1);

nv1:=evalf(subs({t=lam},v1));

nv2:=evalf(subs({t=lam},v2));

printf(" (%8.4f,%8.4f)%13.4f\n",x1pt,x2pt,lam);

x1pt:=nv1;

x2pt:=nv2;

goto(label_7);

label_6;

printf("\n\n-----------------------------------------");

printf("---------------------------------------------");

printf("\n\n Approximate Solution: ");

printf(" (%8.4f,%8.4f)\n",x1pt,x2pt);

Fvalue:=evalf(subs(x1=x1pt,x2=x2pt,f));

printf(" Maximum Functional Value: ");

printf("%21.4f",Fvalue);

printf("%22d",numgeval);

printf("\n Number function evaluations:");

printf("%22d",numfeval);

printf("\n\n-----------------------------------------");

printf("---------------------------------------------");

end:

## Can someone explain what DESol mean as a solution ...

Hello,

I am fairly new to using the Maple software, so I apologize if my question is completely idiotic. Apologies, also, because I could not manage to enter my code as code. When I pressed the button it made the whole text as a code.

I run the following code to seek -if there are any- analytic solutions for the following differential equation.

odeplus := (r^2+L^2)^(5/2)*(diff(f(r), \$(r, 2)))+((15/4)*r*(r^2+L^2)^(1/2)+3*(r^2+L^2)^(5/2)/r)*(diff(f(r), r))+M^2*f(r)/(r^2+L^2)^(5/2)-((5/2)*((r^2+L^2)^(1/2))(l-1)+(55/64)*r^2/(r^2+L^2)^(3/2)+(r^2+L^2)^(5/2)*(l^2+3*l+3/2)/r^2)*f(r)+(((r^2+L^2)^(1/2))(5+(5/2)*l)+(5/8)*r^2/(r^2+L^2)^(3/2)-(r^2+L^2)^(5/2)*(3/2+l)/r^2)*f(r) = 0

and then I do

dsolve(odeplus, f(r))

The solutions that Maple returns is given in terms of DESol. Could anyone try and break it down for me? What is this telling me and if I can indeed from the output obtain analytic solutions? Is this some sort of operator acting on something?

## Add IsPrime condition in a fonction SOLVE( EQNS,[x...

Hello ,

Iam new with maple, and iam trying to solve an equation using prime numbers. The equation is display as follow.

eqns := {G = x*q, 8695*y = 1341*q};

Iam trying to solve with the condition p and q are prime numbers

So is it posible to add condition prime in the solve fonction ? solve(eqns*[x, y]);

## Excessive "Recent" stacking...

I hate it when a user bumps every Question that they've ever asked over the past five years to the top of Recent (aka Active Conversations) stack! This is not the first time that this has happened. I rely heavily on that stack being truly the threads with the most-recent material. Can't something be done about this short of deleting the threads? That seems too drastic: While this user has occasionally been a pest in the past, they've also posted some decent material. There should be some way for a moderator to just reset the stack positions to what they were previously.

## simplify an equation ...

hi.

According to the fhgure attaceh how i can gain the equation (2-27) . I write the equation (2-26) in maple but I couldnot to gain that result.

If possible to reach equation via maple?

Thanks

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