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Hello,

I have this list :
T:=[alpha(t),beta(t)]

I would like to create this list automatically:

Tmod:=[alpha_,beta_]

In other words, how can I remove the 3 characters "(t)" and replace it by "_"

Do you have ideas to do so ?

Thanks a lot for your help

f=x^2.  It's easy to compute the fouier transform. F(y)=fourier(f,x,y).

However, I want to do more. replace the variable y with a new formula g(z)=z^2.

I tried  "subs(y=g,F)". But failed. Need your help.

with(MTM):

f := x^2

x^2

(1)

F := fourier(f, x, y)

-2*Pi*Dirac(2, y)

(2)

g := z^2

z^2

(3)

subs(y = g, F)

-2*Pi*Dirac(2, y) = z^2

(4)

NULL

``

 

Download code.mw

Hi,

 

I was wondering how to go about plotting a Fourier Tranform in Maple.

My assignment is to plot a simple harmonic equation as a Fourier transform, depicting amplitude against fequency.

I've been given: x'' + w^2 x = 0

And want to obtain both the f(x) = a0 sin(wt) + b0cos(wt) form, and a graph of the the amplitude (c^2 =a0^2 + b0^2) against frequency.

I know how to do this on paper but not in Maple, so any help with line commands and layout would be very much appreciated.

 

Thanks

How evaluate system of two integral equation by laplace transform ?

 

with(inttrans):

L := laplace((1/2)*x^2+(1/2)*x^3+(1/12)*x^4 = int(u(t)*(-1+x-t)+v(t)*(1+x-t), t = 0 .. x), x, s);

(s^2+3*s+2)/s^5 = laplace(int(u(t)*(-1+x-t)+v(t)*(1+x-t), t = 0 .. x), x, s)

 

(3*s^2-s+2)/s^5 = laplace(int((1+x-t)*u(t)+(-1+x-t)*v(t), t = 0 .. x), x, s)

(1)

``

 

Download Qu_2_mapel.mwQu_2_mapel.mw

In Maple 15 it seems that plottools:-transform only accepts this form of conditional statement:  

`if`(conditional expression, true expression, false expression).

Is there any way to have plottools:-transform process more than one condition? Do later versions of Maple permit this?

Hi everyone,

 

Consider this maple 18 doc: Euler18.mw

 

The code is regular code for Julia sets of the exponential.

 

To see how the Julia set behaves at infinity, I apply the transform mu(z)=1/z.

 

The plot3d command correctly plots the Julia set at an appropriate neighborhood of infinity, but:

1) Axes are not transformed

2) Saving as .eps produces an empty plot, sans the axes (plot is saved correctly, when not applying mu(z))

 

Is there any trick to force the axes to also show correctly with the transformed ranges?

Seems that this misalignment is bothering the .eps renderer, which probably plots the graph in twilight zone, given the false ranges of the untransformed axes.

 

Any ideas on how to force the saveas .eps to work in this case?

 

Many thanks,

Yiannis

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?

Thanks!
Uwe



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.mw

 

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,
            Pi-arcsin(3/5)..3*Pi/2),
  plottools[arc]([0,r], r, Pi..Pi+arcsin(15/17)),
  plottools[arc]([0, 2*r], 2*r,
            Pi+arcsin(3/5)..Pi+arcsin(63/65)),
  plottools[arc]([0,4*r], 4*r,
            Pi+arcsin(15/17)..Pi+arcsin(63/65)));

  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:

smithChart(1);
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


restart;

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;

print(f);
print(t);

but the problem is that i cant seem to evaluate

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

Hallo:

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.

Thanks

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);

to 

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

 or to

 int(f(u*t)*exp(-t), t=0..infinity);

Cheers!

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.

Hello,

Good day.

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

Thank you in advance.

Try_for_Second_Grade_Fluid.mw

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

hugo

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)

therefore: 

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: 

C(t)=-n(t)+(rho_0^2+rho(t)^2)/(2*l*alpha*K_c)+((Beta+l*lambda-rho_0)*n_0)/(l*lambda)

 

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

Any help would be greatly Appreciated! 

 

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