I am having trouble getting Maple 2017.3 with latest Physics update to give solution to Burger's PDE for viscous fluid flow with the following initial condition. May be I am not doing something right. I tried different HINTS, but no luck.

Maple can solve the PDE without the initial conditions.

May be a Maple expert can find work around or show what I might be doing wrong.

restart;
pde := diff(u(x, t), t) + u(x, t)*diff(u(x, t), x) = mu*diff(u(x,t),x$2);
ic  := u(x,0) = PIECEWISE([0,x>=0],[1,x<0]);
sol := pdsolve({pde,ic}, u(x, t)) assuming mu>0;

Maple returns () as solution.

This PDE can be solved analytically. Here is Mathematica' solution

ClearAll[u,x,y,mu]
pde = D[u[x,t],{t}]+u[x,t]*D[u[x,t],{x}]==mu*D[u[x,t],{x,2}];
ic  = u[x,0]==Piecewise[{{1,x<0},{0,x>=1}}];
sol = DSolve[{pde,ic},u[x,t],{x,t},Assumptions->mu>0]

Is it possible to use Regex to generate a complete list of patterns?

for search pattern in a list of characters

Hi everybody,

Please take the example given in the help pages of DocumentTools[Tabulate] (the one where a cardinal sine is plotted)
Change plot(sin(x)/x) by plot(sin(x),/x, legend=sinc(x))

The legend doesn't appear if the list (named "A" in the help page) is displayed through DocumentTools:-tabulate.

Is it possible to circumvent this problem ?

TIA

i get wrong solution in maximize. i have to get a approximate 0.18 but i get 0.1

restart;
with(Optimization);
app := proc (x) options operator, arrow; 0.14546e-1*sin(3.141592654*x)+(-1)*0.50512e-2*sin(6.283185308*x)+0.19918e-2*sin(9.424777962*x) end proc;
ex := proc (x) options operator, arrow; evalf(-AiryAi(2^(2/3)*x)*(5*3^(5/6)-9*AiryBi(2^(2/3))*GAMMA(2/3))/(8*AiryAi(2^(2/3))*3^(5/6)-8*AiryBi(2^(2/3))*3^(1/3))-AiryBi(2^(2/3)*x)*(9*AiryAi(2^(2/3))*GAMMA(2/3)-5*3^(1/3))/(8*AiryAi(2^(2/3))*3^(5/6)-8*AiryBi(2^(2/3))*3^(1/3))+(1/4)*x^3+3/8) end proc;
plot([100*abs(app(x)-ex(x))], x = 0 .. 1)
Maximize(100*(abs(app(x)-ex(x))), x = 0 .. 1);
 

This is on Maple 2017.3 under windows

After obtaining solution from pdsolve(), I tried to see if Maple can convert it to hyperbolic trig functions by calling `convert(sol,trigh)`. 

I waited and waited and nothing happened. Then clicked on the `interrupt current operation` button at top of menu. 

But I found that mserver.exe has hanged in a loop. Taking 100% CPU and still running. So Had to terminate it from task manager.

Question is: It is ok if Maple can't do the conversion, but why does it hang? Maybe if I want for one hr it will finish, I do not know. But the important part, why does `interrupt current operation` does not work, in the sense that the mserver.exe is still running?

Is this common thing to happen? Should this be fixed? 

Here is example

restart;
interface(showassumed=0);
pde:=diff(u(x,y),x$2)+diff(u(x,y),y$2)=0;
f:=x-> piecewise(x>0 and x<1/2, 2*x, x>1/2 and x<1, 2-2*x);
bc:=u(0,y)=0,u(1,y)=0,u(x,0)=f(x),u(x,2)=f(x);
sol:=pdsolve([pde,bc],u(x,y)) assuming x>0,y>0;

The above works OK and generates a solution. Now the next call hangs mserver.exe

convert(sol,trigh);

In case your Maple version can't solve the above PDE. Here is the solution obtained, so you can try this below without having to solve the PDE

sol := u(x, y) = Sum(8*sin((1/2)*n*Pi)*sin(Pi*x*n)*(exp(Pi*n*(3*y-2))-
         exp(Pi*n*(3*y-4))+exp(Pi*y*n)-exp(Pi*n*(y-2)))*exp(-2*Pi*n*(y-2))/(Pi^2*n^2*(exp(4*n*Pi)-1)),
            n = 0 .. infinity);
convert(sol,trigh);

I also tried convert(rhs(sol),trigh); but it made no difference.

This is my code.  It's not appending as I need it to.  Any help would be humbly and gratefully appreciated!

Download Sort4_320.mw

How can i print maple file? when ever i press ctrl+ p it never responce any thing can we print maple file directly? if yes then please how?

Hello 

how can I write a loop of two variables (i,j )for this formula?

where m& n are fixed numbers.

looking forward to hearing from you.

Thanks

Download piecewise-strange.mw

how can save of resultes as matrix in file.dat?

I am trying to make a library, and therfore package that contains a bunch of objects that inherit from each other.

I understand how to create objects that inherit from one another and my code here works fine:

module ParentObject()
   option object;
end module;

module ChildObject()
   option object(ParentObject);
end module;

However when I put it all in a package with code below:

module Package()
   option package;
   export ParentObject, ChildObject;
   
   module ParentObject()
      option object;
   end module;

   module ChildObject()
      option object(ParentObject);
   end module;

end module;

I get the error "Error, argument of option object(ParentObject) refer to another object in module Package:-ChildObject".

Any sugguestions?

Near the top of the large loop at the bottom of the uploaded worksheet IntSect is copied to IntSectRoll.

IntSectRoll is then modified several times within the loop. However IntSect also changes content even though there are no commands within the loop to cause this.

To avoid this is the reason IntSect is recreated from previous data each time before it is copied.

Is this a bug in my worksheet or in Maple 2016?

Constant_Diameter.mw

The theory behind the worksheet is described, without attribution, in the book The Penguin Dictionary of Curious and Interesting Geometry by David G. Wells.

Does this theory have a name and a discoverer?

f(x)=sqrt(sin(x)); x over the intervall [0,T]

can anyone help me to find this integral ?

I might be doing something wrong since I expected Maple to be able to solve this. Could some Maple manage to make Maple solve the following beam PDE problem taken from a textbook?

This is what I tried.

restart;
pde:=diff(u(x,t),t$2)+diff(u(x,t),x$4)=0;
bc:=u(0,t)=-12*t^2,u(1,t)=1-12*t^2,D[1,1](u)(0,t)=0,D[1,1](u)(1,t)=12;
ic:=u(x,0)=x^4,D[2](u)(x,0)=0;
sol:=pdsolve({pde,ic,bc},u(x,t));

But Maple returns no solution.

I am using Maple 2017.3 on windows.

When I enter this code:

de3a := diff(x(t), t) = (x(t))(1-.5*x(t)-.5*y(t)); de3b := diff(y(t), t) = (y(t))(-.25+.5*x(t));
sys3 = {de3a, de3b};

window := x = -1 .. 3, y = -1 .. 3;
DEplot(sys3, [x(t), y(t)], t = 0 .. 14, window);

I get the error message "Error, (in DEtools/DEplot) system must have same number of dependent variables as DE's." What am I doing wrong? I'm just trying to create a plot on the phase plane.