HHow do i correct "error, illegal use of an object as a name"

Hello everyone,

I am trying to solve a system of 4 ODEs that describe a physical system, however, I get the message:

Error, (in dsolve/numeric/bvp) matrix is singular

Any help is much appreciated. The initial conditions are such that to find solution in steady state, that means, v(0)=v(period) and so on with all variables.

Download LLCcircuit_SteadyState_numerical.mw

Hi, I'm trying to solve auxilary equation to find its familes but I don't know what I'm doing wrong as I'm using following code:

famtemp := (diff(z(xi), xi))^2-a*z(xi)^2-b*z(xi)^3-c*z(xi)^4;

fam1 := simplify(`assuming`([dsolve(famtemp)], [b::real, a::real, c::real, -4*a*c+b^2 > 0, a > 0]))

I want to get the following family:

fam1 := 2*a*sech(sqrt(a)*xi)/(sqrt(-4*a*c+b^2)-b*sech(sqrt(a)*xi));

I hope someone will help me to solve it.

Thanks

have table like table(symmetric, [() = x]) from other code not mine, strange syntax

how to extract x from table thanks

Here is my try to integrate the expression L with trapozoid or simpson 

numerical_int.mw

Hello Everyone,

I am currently trying to tidy up my worksheet and hide all of the script/code that I wrote in the Maple 2D-Math within the execution script of buttons etc.
Was going well so far until I started transferring code where I was using a lot of symbolic math (if I understood correctly)
There is one instance where I have a variable chi which equals x divided by a.
a being a number, e.g. 5000, while x is and remains a variable.
No problem in 2D-Math as the unknown x is dragged through all following equations.

Not so in the code editor, I think. Doing the calculation results not in x/5000, but in this:


It keeps getting worse because this term will be derived, assembled into a matrix, etc. where the expressions are getting ridiculous:


Without getting into the details of what my script should do, I believe this is a very general issue, not specific to my code.

Is the code editor / "Code when Used/Clicked" not capable of symbolic math? Oder is there some setting that could potentially help me?

Best Regards,
Lennart
 

Hello (again)

I thought I won't need help with that type of question but I came across an example that says otherwise.  Here it is

vars:=[x,y,z];

model7 := [x*(-RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)-5/4)+y*alpha[1, 2]-33/(32*RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)), x*z*alpha[2, 6]+y*RootOf(64*_Z^3+80*_Z^2+1104*_Z+561), x^2*(17*RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)+17)/(alpha[1, 2]*alpha[2, 6])-17*x*y/alpha[2, 6]+2*z*x-z-(163/32+RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)^2+5*RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)*(1/4))/(alpha[1, 2]*alpha[2, 6])]

then I issued the command 

map(w->coeffs(w,vars),model7);

to get 

 

[-33/(32*RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)), -RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)-5/4, alpha[1, 2], RootOf(64*_Z^3+80*_Z^2+1104*_Z+561), alpha[2, 6], -(163/32+RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)^2+5*RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)*(1/4))/(alpha[1, 2]*alpha[2, 6]), -1, (17*RootOf(64*_Z^3+80*_Z^2+1104*_Z+561)+17)/(alpha[1, 2]*alpha[2, 6]), -17/alpha[2, 6], 2]

clearly the order does not follow model7's.  

I have also tried

[seq(coeffs(expand(model7[i]), indets(model7[i], suffixed({vars[]}))),i=1..nops(model7))];

Is there a solution to it?

Many thanks (again)

 

Ed

 

 

Error, (in PDEtools/NumerDenom) invalid input: `PDEtools/NumerDenom` expects its 1st argument, ee, to be of type algebraic, but received {[(s_j*e^sigma*b^m*`σ_m`*y_i-s_j*e^sigma*beta*`σ_i`+s_j*e^sigma*b_ilo+(1/2)*b^(m+2)*`σ_j`*e^sigma*`σ_m`*y_i-b^2*`σ_j`*e^sigma*beta*`σ_i`+(1/2)*b^2*`σ_j`*e^sigma*b_ilo-(1/2)*b^(2*m)*`σ_m`^2*b_j*e^sigma*y_i+(1/2)*b^m*`σ_m`*b_j*e^sigma*beta*`σ_i`-(1/2)*b^m*`σ_m`*b_j*e^sigma*b_ilo+b_j*(s_ilo+(1/2)*(b^2*`σ_i`-b^m*`σ_m`*beta)*_lo)+b_j*(s_jlo+(1/2)*(b^2*`σ_j`-b^m*`σ_m`*beta)*_lo)+s_i*e^sigma*b^m*`σ_m`*y_j-s_i*e^sigma*be... when I use simplify I have this error. please guide me Saberali

Hello everyone, thank you in advance

I am trying to plot two functions in the same graph. I didn't realize how to copy the real functions here but:

At the same 3D plot

I need to use the function F1(x,xi,k,B) for values of x*xi <6  and other function F2(x,xi,k,B) for values of x*xi  >= 6

Thank you again and sorry for my rusty English.
 

I attached a file with these 2 functions Functions_MAPLE_PLOT_TOGETHER.mw

Hello

I know that anames( 'user' ) recovers the contents of the workspace but I wonder whether it would be possible to recover only the contents of each m-file read within a worksheet.  

Many thanks

Ed

 

What is the problem with the initialconsiditions that caused this error?

"Error, (in dsolve/numeric/DAE/initial) missing initial conditions for the following: {Integer}"

Thanks.

I'm having trouble connecting from Maple on Windows 10 to MSQL Server. I tried Microsoft recommended drivers such as sqljdbc_6.4.0.0, did (as I thought) all required steps. The only invariable result I get is "Cannot load driver". I was wandering if anyone had implemented such a construction. Driver name & version , connection string and Java version would be greatly appreciated. Another option is to have any driver, which connects to any of standard databases (Oracle, MySQL).  The only limitation is- it must be from Windows 7 or 10.
          Thanks.
           A.B.

Hi all, I would be most grateful if I could get some help with solving the tasks below using Maple.

Given the function: mx''(t)+cx'(t)+kx(t)= F_y(t)

1. Rewrite the equation above to a system of 1. order differential equations, by defining the two variables x_1(t) = x(t) and x_2(t)=x'(t) (Hint what is x'(t)?) This gives the first differential equation in the system. What is x_2'(t)?
    
2. Write the equations as a linear system when the outer force F_y(t) is the influence and the position x_1(t) is the answer, in other words give the system matrix A and the vectors b and r.
    
3. I'm given the constants m = 5kg, c = 3Ns/m and k = 20 N/m and I'm trying to find the transfer function of the system.
    
4. Give the systems transfer function H(s) and draw the graphs for the amplitude and phase characteristic.

Thank you!

 

 

hye, can someone help me to solve nonlinear schrodinger equation using maple? i attach with document

solution_nonlinear.pdf