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Hallo everybody,

I just started to use maple and I think I need some help from more experienced users.
I would like to transform the stationary Navier Stokes equations to toroidal coordinates.

The definition of my coordinate system is as follows:
x = -r * cos(sigma)
y = cos(Theta) * ( R + r * sin(sigma) )
z = sin(Theta) * ( R + r * sin(sigma) )

I tried to define the coordinate system and transform each term of the equation:

div( rho * CC) = -grad(p) + div(Tau)

I can transform the pressure gradient. However, I get an error for the divergence of the tensors.
Could someone please give me a hint on how to get the divergences?


My code is printed below:

restart: with(plots): with(LinearAlgebra): with(VectorCalculus): with(linalg):

#torus defintion
x := -r*cos(sigma);
y := cos(Theta)*(R+r*sin(sigma));
z := sin(Theta)*(R+r*sin(sigma));
R := .35;
AddCoordinates(torus1[r, sigma, Theta], [cos(Theta)*(R+r*sin(sigma)), sin(Theta)*(R+r*sin(sigma)), -r*cos(sigma)]);
SetCoordinates(torus1[r, sigma, Theta]);

#pressure gradient
PressureGradient := Gradient(p(r, sigma, Theta, t));

#left hand side
c := vector(3, ([Cr, Ctheta, Cx])(r, sigma, Theta, t));
rhoCC := rho*multiply(c, transpose(c));
LHS := Divergence(rhoCC)

Hi all, 

I'm trying to implement the smithChart on Maple, but this error "Error, (in unknown) invalid transform: output is not 2 or 3 element" keeps popping up for some reason. I have no idea how to fix it. Can anyone help me with this? Here is the smithChart:


smithChart := proc(r)
  local i, a, b, c;
   a := PLOT(seq(plottools[arc]([-i*r/4, 0], i*r/4, 0..Pi),
                 i = 1..4),

  plottools[arc]([0, r/2], r/2,
  plottools[arc]([0,r], r, Pi..Pi+arcsin(15/17)),
  plottools[arc]([0, 2*r], 2*r,
  plottools[arc]([0,4*r], 4*r,

  b := plottools[transform]((x, y) -> [x-y])(a);
  c := plottools[line]([0,0], [-2*r, 0]):
  plots[display](a, b, c, axes = none, scaling = constrained, args[2..nargs]);
  end proc:

Error, (in unknown) invalid transform: output is not 2 or 3 elements

hello everyone. I have an undergradute project i'm currently working on and I'm stuck where I have to use the Differential Transforms Method to solve a problem with boundary conditions at infinity


Digits := 5;

F[0] := 0; F[1] := 0; F[2] := (1/2)*A; T[0] := 1; T[1] := B; M := 2; S := 1;

for k from 0 to 10 do F[k+3] := (2*(sum((r+1)*F[r+1]*(k+1-r)*F[k+1-r], r = 0 .. k))-T[k]-3*(sum((k+1-r)*(k+2-r)*F[r]*F[k+2-r], r = 0 .. k))-M*(k+1)*F[k+1])*factorial(k)/factorial(k+3);

T[k+2] := (-3*(sum((k+1-r)*F[r]*T[k+1-r], r = 0 .. k))-S*T[k])*factorial(k)/factorial(k+2)

end do; f := 0; t := 0;

for k from 0 to 10 do

f := f+F[k]*x^k;

t := t+T[k]*x^k end do;


but the problem is that i cant seem to evaluate

or higer diagonal pade-approximant. any help will be greatly appreciated. thank you.


I am trying to find the inverse fourier transform given a vector (of real) as input. I get the following error message:

Error, (in DiscreteTransforms:-InverseFourierTransform) entries of input data must all evaluate to complex floats, got '[.7644453211]'

I am unable to understand this message. I would much appreciate help to resolve this issue.


How can I access the Laplace Transform built-in package?

I want to try to modify it for something like this,

 int(f(t)*exp(-s*t), t=0..infinity);


 int(f(u*t)*exp(-s*t), t=0..infinity);

 or to

 int(f(u*t)*exp(-t), t=0..infinity);


I have recently come across this queastion regarding Z-transforms in maple and am struggling with how to complete the question. Any steps on how to proceed with the folloqwing questions would be greatly appreciated. I have done the first part but cannot fathom where to go with this one.

1. For the difference equation

x[n+2]-(α+β)x[n+1]+α*β*x[n]=n/3^n,  x[0]=a, x[1]=b,

(a) Find the general solution for x[n] in terms of the parameters α,β,a and b


(b)Find the solutions for ithe two cases α=-β and α=β


(c)Examine both solutions found in (b) when α=1, for various values of a and b, choosing values to demonstrate different behaviours of the solutions.


Thanks for reading, any help with steps would be great.


Good day.

How to avoid float(undefined) for v3, v4,v5 in this problem.

Thank you in advance.

I'm trying to use Maple to show that the Hilbert transform of the natural log of |H(jw)| is -arctan(H(jw))

for a minimum phase network; The network I choose is the simplest filter there exists i.e. a low pass RC-filter

with transfer function H(jw)=1/(1+tau*j*omega) therefore |H(jw)|=1/sqrt(1+(tau*omega)^2))

Here is what I did:

assume(omega > 0); assume(tau > 0); interface(showassumed = 0);

result5 := (int((1/2)*log(1+(tau*nu)^2)/(nu-omega), nu = -infinity .. infinity, CauchyPrincipalValue))/Pi

simplify(result5, symbolic)


unfortunately this does not give me the expected result: -arctan(w*tau*omega)

can anyone here tell me what the right way to do it is?


thanks in advance


I am trying to recreate journal work for validating using another computer program so I am trying to use maple to solve the ODE, based on further research I found using laplace might be the best but I am having some trouble.


eq8:=d*(n(t)+C(t))/drho = -rho(t)/(l*alpha*K_c)

given the initial conditions of:

ICs:= n(0) = n_0, rho(0) = rho_0, C(0) = (beta-rho_0)*n_0/(l*lambda)


equation9 := dsolve({equation8, ICs}, {C(t), n(t)}, method = laplace)


Following this process I get the error: 

Error, (in dsolve) invalid initial condition


According to the journal work the solution I am looking for is: 



is there something that I'm doing wrong or missing? 

Any help would be greatly Appreciated! 


Dear all,

I have a question, why is the output of the inverse Laplace transformation if the signal is multiplied by itself not just convoluted in time domain:






I have a long expression with different order derrivatives, that is written in form like that:

-(D[1](f))(x, y)

I'd like to transform it into standard maple form like:


Is there any special procedure to achieve this goal?

Can anyone tell me where I can find tutorial explaining how to solve laplace transform? I need a tutorial that explains starting with simple resolution to advanced resolution.

I need to know if the Software Maple solve, step-by-step series of Fourier and Laplace transforms? The Maple command has to solve step by step series of Fourier and Laplace transforms? or commands show only the direct solution?

I'm trying to solve this system of ODEs by Laplace transform. 

> de1 := d^2*y(t)/dt^2 = y(t)+3*x(t)

> de2 := d^2*x(t)/dt^2 = 4*y(t)-4*exp(t)

with initial conditions 

> ICs := y(0) = 2, (D(y))(0) = 3, x(0) = 1, (D(x))(0) = 2



> deqns := de1, de2


> var := y(t), x(t)


I need to solve it for both y(t) and x(t), I have tried this by:

> dsolve({ICs, deqns}, var, method = laplace)


> dsolve({ICs, deqns}, y(t), method = laplace)

> dsolve({ICs, deqns}, x(t), method = laplace)


However I get this error message:

Error, (in dsolve/process_input) invalid initial condition


Any help is appreciated

Hello everyone,


how exactly do i 3-d plot some data that i have to back-transform first. in 2-d it is so easy. why isnt it in 3d? all i end up with is an all black diagram

please see the file attached

Grateful for some hints



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