Answered
Error ---> Brace indexing is not supported for variables of this type.
clc clear g = 9.81; L = 0.1; m = 0.5; zeta = 2; x0 = 0.25; v0 = 0; tspan = [0 10]; step_sizes = [0.1, 0.05, 0.025...

8 dagar ago | 0

Answered
error lsqcurvefit for integrate function
Replace % Define the model function (vectorized for efficiency) function y = model(theta, x) k0 = theta(1); E0 = theta(2...

8 dagar ago | 0

Answered
How to set Drichlet and Neumann boundary conditions for a set of ode in BVP solver
Is there a possibility that I can set three boundaries (mix between Drichlet and Neumann boundary) for a set of two ODE's? No....

8 dagar ago | 0

Answered
Trying to determine roots of this polynomial (Det)
k = [1750 -750 0; -750 1250 -500; 0 -500 500]; m = [75 0 0; 0 75 0; 0 0 50]; eig(k,m)

8 dagar ago | 1

Answered
Civil engineering coding problem ( I dont know where the problem in my code is and how to solve it, thanks in advance )
"coord" has only three rows, but you try to access coord(4,1) and coord(4,2) which do not exist (see above).

8 dagar ago | 0

Answered
Why I am getting this error message? How to fix it?
Maybe you mean this function: function v = vec(m) %Helper function to turn a matrix of any size into a column vector using (:)...

8 dagar ago | 1

Answered
How to draw a three-dimensional function image corresponding to the analytic expression of a given piecewise function image
f = @(x,y)(4*y-4*x.*y-2*y.^2).*(y<x).*(x+y<1)+2*(1-x).^2.*(y<x).*(x+y>=1)+(4*y-4*y.^2-2*x.^2).*(y>=x).*(x+y<1)+(2-4*x+4*x.*y-2*y...

8 dagar ago | 0

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Answered
Generalized Orr Sommerfield error returned in Eigs Function
I suggest you comment out the command W0 = @(x) lambertw(0,x); like %W0 = @(x) lambertw(0,x); include a function for W0 as ...

9 dagar ago | 0

Answered
How can i solve this problem' when i am running, this message appears: Failure in initial objective function evaluation. FMINUNC cannot continue.
Call your function in which you define the sum of differences squared between real and modelled data for the initial values of y...

9 dagar ago | 1

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Answered
hypergeom function, no output
The hypergeometric function has convergence criteria: Converges if p ≤ q and |z| < ∞. Converges if p = q + 1 and |z| < 1. For ...

10 dagar ago | 1

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Answered
How to plot a simple wave equation using method of lines?
n = 100; m = 100; tf = 1; dx = 1/n; x = linspace(0,1,n+1)'; tspan = linspace(0,tf,m+1); y0 = [sin(2*pi*x);zeros(n+1,1)]; %[t...

10 dagar ago | 0

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Answered
Analytical solution of 1-D transient heat transfer
I'd compare with the solution from "pdepe": m = 1; Ri = 0.05; nd = 20; r = linspace(0,Ri,nd); t = [0 100 600 1800 3600 5000...

11 dagar ago | 0

Answered
Solve Nonlinear ODE Symbolically
This is a nonlinear system of ODEs. An analytical solution with symbolic math is not possible. The only way to solve it is nume...

12 dagar ago | 1

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Answered
Triple intergral for the array valued function
N = cell(2,3); N{1,1} =@(x,y,z) x.^2+y.^2+z.^2; N{1,2} =@(x,y,z) x.^2+y.^2+z.^2; N{1,3} =@(x,y,z) x.^2; N{2,1} =@(x,y,z) y....

12 dagar ago | 0

Answered
does "generalized Neumann" boundary condition include actual Neumann boundary condition?
Is there maybe a workaround (like change of variables) to solve these problems? No. All Neumann boundary conditions are related...

12 dagar ago | 0

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Answered
Graphing 1D Diffusion in 2 Compartments - Possible Issue with ODE solver
In my opinion, you have the following conditions at the interface x = h_D: (1) D_D*dC_D/dx = D_R*dC_R/dx (2) C_R = phi*C_D (or...

13 dagar ago | 0

Answered
I want to optimize an ODE system of equations with constraints
I ran your code with k in the order of 0.1,1 and 10, but it seems the k-values have amost no influence on the result of the inte...

13 dagar ago | 0

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Answered
Solving edge-value problems with unknown intervals
Define a dimensionless variable x' = x/l1 and transform your equation to the form dY/dx' = ... which has to be solved in [0 1]. ...

13 dagar ago | 1

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How to calculate a composite triple integral with exponential function?
Setting l, r and s to zero will cause problems because you divide by these variables. But also changing integral2(@(s,l)array...

13 dagar ago | 0

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Answered
Error using lsqncommon Lower and upper bounds not supported with complex-valued initial function or Jacobian evaluation.
If you use "fmincon" and (f(x,xdata)-ydata)' * (f(x,xdata)-ydata) as objective function, complex numbers don't matter because th...

14 dagar ago | 0

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Answered
Solve a complex differential equations system
The main problem with your equations is that they involve a term that has to be evaluated at a boundary point. Otherwise, you co...

14 dagar ago | 0

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an ode with arguements
You have to define your vector of solution variables as y(1) = f, y(2) = f', y(3) = f'', y(4) = T, y(5) = T' and your function...

14 dagar ago | 0

Answered
How to invert a square matrix using Gaussian elimination
The newton update is x_(n+1) = x_n - Df^(-1)*f, not x_(n+1) = x_n + Df^(-1)*f. But you should not explicitly compute the ...

15 dagar ago | 1

Answered
Find Eigenvalues of ODE45 Solution MATLAB
Your system reads z1'= z2 z2' = ( F-(c1+c2)*z2-( ((k1*gamma1+k2*gamma2)*z1^2+k1+k2)*z1+(-k2*gamma2*z1^2-k2)*z3 ) )/m1 z3' = z...

15 dagar ago | 1

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Answered
How to get an expression for a Hypergeometric function with symbiotic variable
MATLAB is not able to find the Inverse Laplace transform of such a complicated function as an analytic expression.

15 dagar ago | 0

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Answered
can someone please help me coding this saturation equations in matlab
m, umax and u have to be defined previously. psi = zeros(m,1); idx = abs(u) > umax; psi(idx) = sign(u(idx)).*min(abs(u(idx)),...

15 dagar ago | 0

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Answered
variable problem of GA
t=[0.015 0.01 0.009 0.012 0.016 0.014 0 0]; w=[0.005 0.004 0.003 0.004 0.006 0.004 0 0]; options = optimoptions( ... 'ga'...

15 dagar ago | 0

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Answered
fmincon solution does not differ from initial guess if I provide gradient
Use SpecifyObjectiveGradient Gradient for the objective function defined by the user. See the description of fun to see how to...

15 dagar ago | 0

Answered
When using integral function to calculate MeijerG function, Matlab will get stuck.
meijerG has a division by 0 at SNR = 0. If you are sure the integral exists at SNR = 0, start with a small value > 0, e.g. aver...

16 dagar ago | 0

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Answered
Set answers of first BVP as new boundary condition for second BVP
"value_at_1" is defined in the script part of your code, but it's not automatically visible in the functions you define. Either ...

16 dagar ago | 0