I have a problem solving a system of PDEs.

The system of PDEs are

PDE01 := -(l^2+1^2)*(diff(v(l, t), t))+(l^2+1^2)*(diff(R(l, t), l, l))+4*l*(diff(R(l, t), l))+4*l*v(l, t)/(l^2+1^2)^(1/4)-6*R(l, t)/(l^2+1^2)+(l^2+1^2)^(1/2)*(-1.1+sqrt(.1))^2*sqrt(24)*u(l, t) = 0

PDE02 := diff(R(l, t), t) = v(l, t)

PDE03 := diff(u(l, t), t)-sqrt((1.1^2-1)/1.1^2)*(diff(u(l, t), l))-2*l*sqrt(1.1^2-1)*u(l, t)/(l^2+1^2) = 0

the initial condisions are

v(l, 0) = 0, R(l, 0) = 0, u(l, 0) = sqrt((l^2+1^2)^(1/2))*10^(-5)*exp(-(l-10)^2/.5^2)

and the BCs are

bdry00 := {((30^2+1^2)/30^2)^(1/4)*v(-30, t) = -((30^2+1^2)/30^2)^(1/2)*(D[1](R))(-30, t), ((30^2+1^2)/30^2)^(1/4)*v(30, t) = -((30^2+1^2)/30^2)^(1/2)*(D[1](R))(30, t), u(-30, t) = sqrt(30^2+1^2)*10^(-5)*exp(-40000), u(30, t) = sqrt(30^2+1^2)*10^(-5)*exp(-10000)}

to solve the system,

I enter

pde := pdsolve({PDE01, PDE02, PDE03}, {bdry00, init00}, time = t, numeric, range = -30 .. 30, timesstep = 1/60, spaceste = 1/254)

then, I failed to get the result constantly.

I tried several cases changing the initial conditions...

Can you let me know what I am doing wrong?

I have a problem with IsMatrixShape. I have in my part of formulation this matrix expression: Q^TI_bQ

While I_b is a symmetric matrix, this matrix expression is clearly symmetric. However, when I try to check this issue with IsMatrixShape command, it returns false. I am extremely confused. Can anyone help me? Thanks in advance.

prob1.mw    prob2.mw

Hi, I don't know why this happened...

If I write the command in new sheet, it runs correctly( prob2.mw).

Second, help me to evaluate N, please...  (prob1.mw)

Regards :-)

Download Question_algsubs_3.27.15.mw

Hi,

I'm using maple to solve non linear DE system. The error below appeared. What to do?

eqd1:={diff(u(x),x)=U(x)}:

eqd2:={diff(v(x),x)=V(x)}:

eqd3:={0.004*x*diff(U(x),x)+(x-8*x*V(x)+0.006*U(x)+(3/2-12*V(x)-8*x*diff(V(x),x))*u(x)=0}:

eqd4:=(0.008*x*(V(x)^2)+2*(0.6+x)*v(x)*V(x)+v(x)*u(x)+(v(x)^2)=0}:

fonc:={U(x),u(x),V(x),v(x)}:

sol:=dsolve(eqd1,eqd2,eqd3,eqd4,fonc}:

Error, (in PDEtools/sdsolve) too many arguments; some or all of the following are wrong: [{U(x), u(x)}, {diff(v(x), x) = V(x)}, {1/250*x*(diff(U(x), x))+(x-8*x*V(x)+3/500)*U(x)+(3/2-12*V(x)-8*x*(diff(V(x), x)))*u(x) = 0}, {1/125*x*V(x)^2+2*(3/5+x)*v(x)*V(x)+v(x)*u(x)+v(x)^2 = 0}]

 

Hi

How can I obtain series expansion of a known mathematical function? for example I Need a command to get a formula for expansion of Bessel function as bellow

Dear all,

I know how interpolating curves using 1D Fourier tranform.

see http://www.mapleprimes.com/questions/121551-Fourier-Serie-And-Discrete-Fourier-Transform

How to use 2D Fourier transform to find a 2D Fourier series to interpolate surfaces as:

f := proc (x, y) options operator, arrow; sin(x)^2+cos(y)^2 end proc

plot3d(f(x, y), x = 0 .. Pi, y = 0 .. Pi)

Or surface data [x,y,f(x,y)].

Thank you

I'm attempting to plot the Nyquist plot for a complex system such that Maple cannot determine the frequency limits automatically, and suggested I use 'range' to specify the frequency limits. How do you do this? For example if you have a system G=1/(s+1), how do you plot the Nyquist plot in the frequency range 0 to 1rad/s?  Thanks

I make a new parameter in MapleSim, but I don't konw why it becomes to something as shown in the above figure.

In MapleSim environment, I can see these code, but I find that I cannot edit them.

Is there a method that I can edit these codes?

Thank you.

Helo friends. Hope you will be fine. I need the command for take the conjugate of exp(I*x). I need the result exp(-I*x), x treated as real number.

PhD (Scholar)
Department of Mathematics

In a plot command, how do I indicate not to show the legend ?

(I know about unchecking "show legend" with a right click, and I have searched mapleprimes.)

Thanks, all !

Is it possible to have Maple display square brackets, instead of a subscript ? (Seperately, I would still like to use subscripts. So, I don't want everything in square-bracket notation.)

Input: 

Evaluates to:

I'd like to plot a surface from three lists in the following way:

For each item in the list X we have a specific curve "plotted" in the plane Y vs Z.

In other terms, we have something like that: each X[i] will be related to two lists, say, Z[1], Z[2], Z[3] and Y[1], Y[2], Y[3], X[i+1] will be related to Z[4],Z[5],Z[6], and Y[4],Y[5],Y[6] and so on...

A very 'thin' surface following this would be, as a example:

X=[1,2]

Y=[[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30]]

Z=[[20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49], [21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50]]

I am looking for some tutorial showing something similar but without any success. Please, any kind of help certainly will be absolutely very appreciated. Thanks in advance! Best regards,

Write a Maple code that performs the Gaussian elimination for an nxn matrix, converting it to an upper triangular matrix. 

(Hint: you will need to use three for .. do loops.)