# Items tagged with maplemaple Tagged Items Feed

### to solve a partial differential equation with mapl...

December 30 2013
1 11

hey i am new here and i have a question,

i have an partial differential equation diff(u(t,x),t$2)=diff(u(t,x),x$2) with the intial value problem u(0,x)=f(x)=1/(1+x^2) and diff(u(0,x),t)=0

and now my question i have already programm it:

> with(inttrans);

with(DEtools);

with(plots);

> with(PDETools);

> k := diff(u(t, x), $(t, 2)) = diff(u(t, x), $(x, 2));
bc := u(0, x) = 1/(1+x^2);
v := diff(u(0, x), t) = 0;
d / d \ d / d \
--- |--- u(t, x)| = --- |--- u(t, x)|
dt \ dt / dx \ dx /
1
u(0, x) = ------
2
1 + x
0 = 0

> pdsolve(k, u(t, x));
print(output redirected...);
u(t, x) = _F1(x + t) + _F2(x - t)

> c := pdsolve({bc, k, v}, u(t, x));
print(output redirected...); # input placeholder

and now question at the last there is nothing does it means that maple can´t solve it with the intial value problem and how can solve it with Fourier-Transformation to x???

can anyone help me please and sorry my englisch is not so good ;)

### command minimize...

December 28 2013
0 7

hey maple followers,

i need, please to find the method used in command "minimize".
i looked into help maple and i found "theorema mean values" as example
thanks!

P.s: minimize not Minimize

### How do I define a unit vector normal to a LineSegm...

December 27 2013
1 2

I'm writing a simple Maple program to test the Generalized Finite Element Method: main_screened_Poisso.mw

When trying to define the Neumann boundary conditions, I have to define a directional derivative dudn=dudx*n. However, I can't seem to define a unit vector normal to Gamma, which is defined by a LineSegments objects.

Other than that, the row reduction is very slow, even though I'm using floating point arithmatic and not exact arithmatic, I believe.

How can I solve these problems? Thanks in advance!

### how to create a matrix ...

December 27 2013
0 2

Hi!

I still have a problem and im looking forward to any suggestions

this is the previous code that i have wrote

P := array([[8, 4], [8, 3], [8, 2], [7, 1], [6, 0], [5, 0], [4, 0], [2, 1], [1, 1], [1, 4]]);

> for j from 2 to 5 do k[j] := j+1;

x[j] := add(P[j, 1], j = j-1 .. j+2);

X[j] := add(P[j, 1]^2, j = j-1 .. j+2);

y[j] := add(P[j, 2], j = j-1 .. j+2);

Y[j] := add(P[j, 2]^2, j = j-1 .. j+2);

xy[j] := add(P[j, 1]*P[j, 2], j = j-1 .. j+2);

cx[j] := evalf(x[j]/k[j]);

cy[j] := evalf(y[j]/k[j]);

c11[j] := evalf(X[j]/k[j]-cx[j]^2);

c22[j] := evalf(Y[j]/k[j]-cy[j]^2);

c12[j] := evalf(xy[j]/k[j]-cx[j]*cy[j]);

C[j] := evalf(Matrix(2, 2, [[c11[j], c12[j]], [c12[j], c22[j]]]));

E[j] := simplify(fnormal(LinearAlgebra[Eigenvalues](C[j])));

if E[j][1] > E[j][2] then a[j] := E[j][2]/(E[j][1]+E[j][2]) else b[j] := E[j][1]/(E[j][1]+E[j][2])

end if;

a[j];b[j]

end do;

now, my question is how to put the output from the above looping in a  matrix form.

in my matrix, i need to call a[j],b[j], E[j][1], E[j][2] and the coordinate points. so my matrix dimension 4 x 5

I guess its a simple task but i tried hard and didnt get it worked.

thank you.

### installation maplesim on windows 8...

December 26 2013
0 7

Hello,

I tried to install maplesim on windows 8 but it didn't work.

However, i have installed microsoft visual c++ express before and i have made the precedure as described in maple that is to say

or

### vigenere cryptanalisis with maple...

December 26 2013
1 12

hi, i have a problem with maple. i took the codes from a book, it should be true but even i copied and past exactly the same, again the maple gave me error which i couldnt solve. could you please help me? how can i correct it ? incorrect codes are below, but if you need all codes i can write here. i need a solution immediately :(

>relativefrequencies := proc(text, language)
evalf(frequencies(text, language)/StringTools:-Length(text))
end proc:
VigenereKeyFind := proc(ciphertext, max:=floor(StringTools:-Length(ciphertext)/15),
{language:=en})
uses StringTools;
local freqs;
freqs := map(x -> relativefrequencies(x, language),
map(Implode, partit(Explode(ciphertext),
keylength(ciphertext, max, :-language=language))));
Implode(map(li -> frequencyanalysis(li, :-language=language), freqs))
end proc;

>VigenereKeyFind(c);
Error, (in VigenereKeyFind) &rsquo; does not evaluate to a module

### Maple 18 wishlist...

December 23 2013
1 4

A little late in the game, with no Maple 18 wishlist yet I'd like to get it started

granted all wishes for previous versions not yet applied should still, hopefully, be under consideration.

1 - The abitlity to angle x-axis labels.

2 - Textplot option for text to rotate with graph as it is rotated.  Currently all textplot texts are held to the horizontal

### Thanks Maplesoft !!!...

December 23 2013 Maple 17
11 0

Thanks to the community through Maplesoft Mapleprimes that could develop in Computational Mathematics Achievement Day at our institution.

### series replies pt...

December 21 2013
2 3

Dear all,

I have encounter a Maple response but I don't know how to interpret it.

When I tried the following Maple codes:

A := solve( x^4 + x^3 + x^2 + x + 1  = n, x ):

asympt( A, n, 2 )

Maple responded with a mysterious "pt".  What is going on?  Any help will be appreciated!

Cheers, Yen-chi Roger Lin

Assistant Professor in Mathematics

National Taiwan Normal University

### ¿Does Maple 17 in that way has helped in the devel...

December 19 2013
4 1

¿Does Maple 17 in that way has helped in the development of complex geometric problems?

### Why does Maple Crash?...

December 19 2013
0 0

When you use the slider without Do(%MathContainer1 = StandardError(Variance, R)):
everything works ok but when you add Do(%MathContainer1 = StandardError(Variance, R)):
Maple Crashes.....

Strange...

LL_102)_Covariance_M.mw

### Quick question about the solve function...

December 19 2013
1 5

EDIT:EDIT: I found what I was looking for. Thanks!

eq:=(V^(1-r/(r-s))*V*k/(r-2*s)+_C1)*V^(r/(r-s))=0;

$\left&space;(&space;\frac{V^{1-\left&space;(&space;\frac{r}{r-s}&space;\right&space;)}*V*k}{r-2*s}+C1&space;\right&space;)&space;*V^{\frac{r}{r-s}}=0$

solve(eq,C1);

Can anyone tell me why nothing happens when I solve the above equation for C1.

I've been coming across this problem a few times lately, but sometimes when the equations are less complicated it does work from time to time.

Any help would be greatly appreciated.

EDIT:  Thanks Markiyan Hirnyk

But I'm still having some trouble.

f:=t->(-r*t+s*t+V)^(r/(r-s));

eq2:=diff(C*f(t),t)+C*f(t)*r/(V+s*t-r*t)=s*k*t;

solve(eq2,C);

When I try solving eq2 nothing happens.

This time C is just a variable I used and not one Maple generated.

So why doesn't it work with this particular equation?

### Fitting data and starting at zero...

December 15 2013
1 4

I have to make a plot for experimental data where x corresponds to time and y is the concentration. So I loaded the values in two lists, ran fit to least squares and got the best fitting curve (it's linear). However, the line has to start at (0,0). How can I Maple to do that for me?

### Simple calculation… BiG Problem...

December 14 2013
1 2

Hi to you,

Lets do this;

.1234567891*10^10 +.5 - 1234567892;
0.

the result is -0.5 and not 0.

I'm new in Maple ... can you help to understand the problem?

### How to solve this system of equations with Maple?...

December 12 2013
1 4

I am trying to solve a system of equations with Maple 16, but it keeps returning an error message. I have the following very simple code:

_________________________________________

assume(lambda > 0);
assume(kappa > 0);
assume(omega > 0);

assume(a >= 0);
assume(alpha, 'real');
assume(b >= 0);
assume(beta, 'real');
assume(m >= 0);
assume(mu, 'real');
assume(n >= 0);
assume(nu, 'real');
assume(t >= 0);
assume(tau, 'real');
assume(p >= 0);
assume(psi, 'real');
assume(d >= 0);
assume(delta, 'real');
assume(r >= 0);
assume(rho, 'real');
assume(x >= 0);
assume(xi, 'real');

solve({d^2*lambda^2+r^2*kappa^2+(x^2-1)*omega^2 = 0, (a^2-1)*lambda^2+m^2*kappa^2+t^2*omega^2 = 0, a*exp(-I*alpha)*b*exp(I*beta)*lambda^2+m*exp(-I*mu)*n*exp(I*nu)*kappa^2+t*exp(-I*tau)*p*exp(I*psi)*omega^2 = 0, a*exp(-I*alpha)*d*exp(I*delta)*lambda^2+m*exp(-I*mu)*r*exp(I*rho)*kappa^2+t*exp(-I*tau)*x*exp(I*xi)*omega^2 = 0, b*exp(-I*beta)*d*exp(I*delta)*lambda^2+n*exp(-I*nu)*r*exp(I*rho)*kappa^2+p*exp(-I*psi)*x*exp(I*xi)*omega^2 = 0}, {a, b, d, m, mu, n, nu, p, psi, r, rho, t, tau, x, xi, alpha, beta, delta}, useassumptions, maxsols = 10)

_________________________________________

When this piece of code is executed, I receive the following error message:

Error, (in Engine:-Tarjan) invalid input: subs received {0 <= x_8, 0 <= x_10, 0 <= x_12}, which is not valid for its 1st argument

What does this mean? How can I find solutions to this system of equations? (I know that there exists at least one solution, and I am figuring out whether there exist more.)

Any help would be greatly appreciated.

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