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This is the first presentation of updates for the DE and Mathematical Functions programs of Maple 18. It includes several improvements, all in the Mathematical Functions sector, as well as some fixes. The update and instructions for its installation are available on the Maplesoft R&D webpage for DEs and mathematical functions. Some of the items below were mentioned here in Mapleprimes - you are welcome to present suggestions or issues; if possible they will be addressed right away in the next update.

  • Filling gaps in the FunctionAdvisor regarding all the 6 complex components: abs, argument, conjugate, Im, Re, signum, as well as regarding Heaviside (step function), Dirac, min and max.
  • Fix the simplification and differentation rule for doublefactorial
  • Make convert(..., hypergeometric) work the same way as convert(blabla, hypergeom)
  • Implement integral forms for Heaviside(z) and JacobiAM(z, k) via convert(..., Int)
  • Implement appropriate display for the inert %intat function as well as its conversion to the inert Int
  • Make the FunctionAdvisor/DE return not just the PDE system satisfied by f(z, k) = JacobiAM(z, k)and also (new) the ODE satisfied by f(z) = JacobiAM(z, k)
  • Fix conversion rule from Heaviside(z) to Sum
  • Fix unexpected error interruption when differentiating min(...) and max(...) containing more than three arguments
  • Fix issue in simplify/conjugate
  • Improvement in expand/int: factors in disguise are put outside the integration sign
  • Various improvements in the case of multiple integrals involving the Dirac function
  • Make Intat fully inert (before it was evaluating its arguments)
  • Make value of inert indexed objects work

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

I am trying to solve an equation by continuation method (one vairable and one parameter) containing more than 1000 terms and also hight exponents like 800. I want to get omega' values for different 'p' values.The maple file  is appended below. the link is maple_equation.mw

Many thanks in advance.


Hi,   I want to substitute every  U[jj+1,-1] by U[jj+1,1] in these lines. Many thanks to send your remarks.
U[jj+1,-1]:=U[jj+1,1];

for jj from 1 to M do:
  sys[jj] := eval(BTCS_general,j=jj);
od;

subs(U[jj,M+2]=U[jj,M]; U[jj+1,-1]=U[jj+1,1], sys);

  Why in this equation U[jj+1,-1] doesnt changed by U[jj+1,1];
                    s u[i + 1, -1]   4 s u[i + 1, 0]   6 s u[i + 1, 1]
      u[i + 1, 1] + -------------- - --------------- + ---------------
                           4                4                 4       
                          h                h                 h        

           4 s u[i + 1, 2]   s u[i + 1, 3]          
         - --------------- + ------------- = u[i, 1]
                  4                4                
                 h                h                 


Hi ;

I need your help to write the system contains all these equation:



# system 1
u[0,0]:=(1/2)*(u[1,0]+u[0,1]);
u[0,N+1]:=(1/2)*(u[0,N]+u[1,N+1]);
u[N+1,N+1]:=(1/2)*(u[N+1,N]+u[N,N+1]);
u[N+1,0]:=(1/2)*(u[N,0]+u[N+1,1]);
# system 2
for j from 1 to N do
u[0, j] := (1/4)*(u[1,j]+u[1,j]+u[0, j-1]+u[0,j+1]-f[0,j]*h^2);
end do;
# System 3
for j from 1 to N do
u[N+1, j] := (1/4)*(u[N, j]+u[N-1,j]+u[N+1, j-1]+u[N+1, j+1]-f[N+1,j]*h^2);
end do;
system4
 eqs := [ seq(seq(Stencil[1](h,i,j,u,f),i=1..N),j=1..N)];

How can collect these system 1 system2, system3 ans system4 in a set with one name.


sys:=[eqs,system3,system2,system2]; ( sys: here contains all the equation).

Thanks you.

 

Hi,

Please I need help in this subject. I would like to compare the numerical solution obtained by finite difference and pdsolve/numeric.

The equation considred is  diffusion Equation using Forward-time centered-space (FTCS) stencil
The code work well with Dirichlet boundary condition, but I want to let  x=-1  Dirichlet boundary condition but on x=1, we put a Neumann condition likeeval( diff(u(t,x),x),x=1)=1. Thank you very much to put the necessary in the attached code the changment.      
Many thinks.

Change_boundary_condition_in_procedure.mw    

Hi Maple-Prime-ers!

I have a system of equations, containing 18 variables and 13 equations, making this a 5 degree of freedom (DOF) system.  I would like to analytically solve each of the equations in terms of each of these DOFs.  Normally I would use solve(system, dof_variables) to accomplish this, but it doesn't return anything.  Not even [].

I can solve this system by hand.  I've included a hand-solution involving isolate() and subs() in the attached worksheet.  I'm looking to incorporate this in an optimization algorithm with varying system, so I would like an automated way of doing this.

Does anybody have any suggestions to get solve to work as intended?

 

3driversys_FD_BRAKE_ICE_GEN.mw

 

Here is the system I am talking about:

 

 

The free variables are:  {FD_T, FD_W, ICE_T, EM2_T, BRAKE_T}

 

I'm looking for a solution in this form:

 

 

 

 

 

Hi,

I try to solve this equation using pdsolve but there is no results.
restart:
with(PDEtools):
with(plots):

Eq:=diff(u(t,x), t$2) =diff(u(t,x),x$2)+sin(u(t,x));

pdsolve(Eq);

Thank you for your help.

 

Hai everyone. I used maple 12 and have an equation as follow:

int(int(lambda[v]*lambda[t]*exp(-lambda[v]*v-lambda[t]*t), v = (1/2)*(q[p]+q[p]*t[c]*t+2*S[di]*h*t)/(h*t) .. infinity), t = 0 .. infinity)

 

and try to get an outcome as follow:

However, I cannot get the outcome like I want. The maple just diplay the equation. Any tips or suggestion?

Thanks

Regards,

Dolby87

What is the weak solution integral equation for 

du(x)/dx2 -(1+x2 ) u(x)-1=0

Hello,

Maple needs 827 characters to write a equation of a straight line.
Is that true or what am I doing wrong?   

Can anybody help me or give a direction to handle with such problems?

Putting
  assume(2<alpha , alpha<=4);about (alpha);
before it does not help either.

f:=-(6*(3*alpha^2*(alpha-1+sqrt(alpha^2-3*alpha+2))^4/(alpha-1)^4-12*alpha^2*(alpha-1+sqrt(alpha^2-3*alpha+2))^3/(alpha-1)^3-6*alpha*(alpha-1+sqrt(alpha^2-3*alpha+2))^4/(alpha-1)^4+16*alpha^2*(alpha-1+sqrt(alpha^2-3*alpha+2))^2/(alpha-1)^2+24*alpha*(alpha-1+sqrt(alpha^2-3*alpha+2))^3/(alpha-1)^3+3*(alpha-1+sqrt(alpha^2-3*alpha+2))^4/(alpha-1)^4-8*alpha^2*(alpha-1+sqrt(alpha^2-3*alpha+2))/(alpha-1)-24*alpha*(alpha-1+sqrt(alpha^2-3*alpha+2))^2/(alpha-1)^2-12*(alpha-1+sqrt(alpha^2-3*alpha+2))^3/(alpha-1)^3+8*(alpha-1+sqrt(alpha^2-3*alpha+2))^2/(alpha-1)^2+8*alpha+(8*(alpha-1+sqrt(alpha^2-3*alpha+2)))/(alpha-1)-7))/(alpha*(alpha-1+sqrt(alpha^2-3*alpha+2))^2/(alpha-1)^2-2*alpha*(alpha-1+sqrt(alpha^2-3*alpha+2))/(alpha-1)-(alpha-1+sqrt(alpha^2-3*alpha+2))^2/(alpha-1)^2+(2*(alpha-1+sqrt(alpha^2-3*alpha+2)))/(alpha-1)-1)^4;

Hi all

In matlab software we have a command namely fmincon which minimizes any linear/nonlinear algebric equations subject to linear/nonlinear constraints.

Now my question is that: what is the same command in maple?or how can we minimize linear/nonlinear function subject to linear/nonlinear constraints in maple?

thanks a lot

Mahmood   Dadkhah

Ph.D Candidate

Applied Mathematics Department

Hi,

What is the reason/Why: 

 

Error, (in dsolve/numeric/bvp) unable to achieve requested accuracy of 0.1e-5 with maximum 128 point mesh (was able to get 0.66e-1), consider increasing `maxmesh` or using larger `abserr`

Thanks for the help :)

The equation

x^7+14*x^4+35*x^3+14*x^2+7*x+88 = 0

has the unique real root

x = (1+sqrt(2))^(1/7)+(1-sqrt(2))^(1/7)-(3+2*sqrt(2))^(1/7)-(3-2*sqrt(2))^(1/7).

Here is its verification:

Is it possible to find that in Maple? I unsuccessfully tried the solve command with the explicit option.

 

 

 

Hi ,

I would like to resolve the Kortweg and de Devries equation :

> KDV2:= diff( u(X,T), T)+ 6*u(X,T)*diff(u(X,T),X)+ diff(u(X,T),X$3);

 

I used pdsolve but I have a problem to enter the IBC :

I want

u(infinity, t) =0
u( -infinity, t )=0

u ( x, 0 ) = 1


So I did :


> SOL:=pdsolve(diff( u(X,T), T)+ 6*u(X,T)*diff(u(X,T),X)+ diff(u(X,T),X$3)=0,{u(-10, T) = 0, u(10, T) = 0, u(X, 0) =1},numeric,time=T,range=-10..10);

 

But it doesn't work.

( I remplace infinity by 10 because then I want the graphic representation of the solution )

Could you help me please ?  

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