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Numerical Methods for Singular systems
The loop index i does not equal time t. So expressions like d_1=floor(1.5+sin(0.5*i*h)); x1(:,i-d_1-1) x2(:,i-d_1-1) x3(:,i...

etwa 2 Monate vor | 1

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Does anyone know how to use an IF statement with ODE's? I am trying to create an IF statement sigma > 0 , tau > 0 if dx(3,1) > 0, dx(1,1) > 0 and sigma = 0 , tau = 0 otherwise
You mean % linear ODEs dx(1,1) = alpha * y - beta * r * y; dx(3,1) = - theta * w + lambda * y * w - mu * w * w; if dx(1,...

etwa 2 Monate vor | 2

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Integral Recurrence Formula Implementation
This seems to work: xl = 0; xu = 4; q = 12; C1 = 2; vl = (xl*sqrt(xl^2+C1^2)+C1^2*log(xl+sqrt(xl^2+C1^2)))/2; vu = (xu*sqr...

etwa 2 Monate vor | 0

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How to solve a thermal model? NEED HELP!!
Params = load('Params.mat'); S_matrix = load('S_matrix.mat'); MC = Params.MC; Q = Params.Q; S = S_matrix.S; T0 = 298.15; T...

etwa 2 Monate vor | 1

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Apply Dirichlet BC on Vertex
Is there a way to use a function and logic (example below) to have the code use Neumann on edges 1 & 4 but when x=xmax and y=ymi...

etwa 2 Monate vor | 0

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I have a problem with 2D heat conduction develop a computer code to solve the 2D heat conduction equation:∂2T /∂x2 + ∂2T/ ∂y2 = 0, gradient don't change when iterations increase, please help me
The maximum gradient is always in the left and right upper corner point with value (1-0)/(1/40) = 40. So it won't change in the ...

etwa 2 Monate vor | 1

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How to solve a thermal model? NEED HELP!!
I get these curves with your equations and your data. T0 = 298.15; T_air = 293.15; G_air = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 22...

etwa 2 Monate vor | 0

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quadgk AbsTol/RelTol parameters combinations
umin = 1e-16; f = @(t,u) exp(-t*u.^2)./(u.*(besselj(0,u).^2+bessely(0,u).^2)); g = @(u) pi/2 * atan((2*double(eulergamma)-log(...

etwa 2 Monate vor | 0

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Solve not returning values after first iteration?
You overwrite omega3 and omega4 as symbolic variables with numerical values. Replace % Solve the system sol = solve([eq1, eq2...

2 Monate vor | 0

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BVP unknown parameter 2 column vector
You forgot to include "C_L_aoa" as global variable in the script part of your code. clear all clc close all %%%%%%%%%%%%%%%%...

2 Monate vor | 1

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Nonlinear Curve fitting with integrals
This code works for your supplied data: Delta = 0.075; delta = 0.002; D = 0.098E-9; gamma = 2.675E8; Rmin = 0.01e-6; Rmax ...

2 Monate vor | 0

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How to graph coupled differential equations
% Parameters m1 = 4.0; m2 = 6.0; L = 1.5; k = 100.0; % Added missing parameter g = 9.81; F0 = 100; tF = 1; % Initial st...

2 Monate vor | 0

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Nonlinear Curve fitting with integrals
It takes too long to run the code online - try if it produces reasonable results. Maybe you have to set lower and upper bounds f...

2 Monate vor | 0

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Matlab function that tells the full path of from where the function has been called
What about passing the full path where the function is located from the respective functions 2,3,4,5... to function1 ? See htt...

2 Monate vor | 0

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how to deal with discontinuities in solutions to differential equations using ode45
Usually, the differential equations to be solved are much more complicated than yours which makes it impossible to foresee possi...

2 Monate vor | 2

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How to rename a new matrix obtained by adding a row to the previous matrix
A = [1:5; 6:10] B = [A;11*ones(1,size(A,2))]

2 Monate vor | 0

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eventfunction for stopping solver when output becomes complex doesn't work
Try options = odeset('Events', @(t,y)stop(t, y, Vb0, lambda, mb, rhog0, Cw)); [t, y] = ode45(@(t, y) DE(t,y, Vb0, lambda, mb,...

2 Monate vor | 0

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Drawing Bessel function is not possible in that it give me an error
Maybe this is what you want: x=(0:0.01:5).'; i=0:20; hold on for m=0:5 j=sum((-1).^i./(factorial(i).*gamma(i+m+1)).*(x/...

3 Monate vor | 0

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Facing problems in nonlinear system
"pdepe" gives a different solution than your method. Maybe the nonlinear systems have multiple solutions. %%%% Problem_01 %%%% ...

3 Monate vor | 0

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How to code a 1D ODE in MATLAB
Usually, the equation reads dW/dt + U*dW/dx = C (1) If U in this equation is positive, your flow goes from left to right,...

3 Monate vor | 0

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lsqcurvefit Surface Fitting Troubleshooting
There is a problem with your "poly_fun". You have to use poly_fun = @(c,XY) c(1)*XY(:,:,1).^1 + c(2)*XY(:,:,2).^1 + c(3)*XY(:,:...

3 Monate vor | 2

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I have this system of linear equations and i need to solve it for unknowns. how i can solve it in MATLAB? we have 8 unknowns and 8 equations.
@javeria If you want to avoid writing your system as A*X = B, you can use a nonlinear solver like "fsolve". As the system is l...

3 Monate vor | 0

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Finding one real solution with vpasolve
lambda = vpasolve(LCG/B*1/lambda_t==0.75-1/(5.236*CV^2/lambda_t^2+2.4) == 0, lambda_t, [0,inf]);

3 Monate vor | 0

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make function from matrix
t = linspace(0,10,3000).'; a = rand(3000,1); f = @(x)interp1(t,a,x); f(8.336)

3 Monate vor | 0

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I am struggling to format and run a pde as part of a liquid-liquid packed column
K_M = 0.1252; xb_meth = 0.0054; Rho_FAME0 = 0.915; Phid_cho = 0.2352; Vd = 6.1006e-4; kod_meth = 1.0157e-5; ap = 204; Vc ...

3 Monate vor | 0

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trouver un angle avec l'equation de trajectoire d'un projectile
x0 = 0.08; y0 = 0.05; v0 = 2; g = 9.81; syms t x theta eqn1 = x == v0*t*cos(theta) + x0; eqn2 = 0 == v0*t*sin(theta) - 0.5...

3 Monate vor | 0

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using bvp5c evaluate velocity and temperature at specific points
yeval = deval(S,[-1,-0.4,0,0.4,1]); veval = yeval(1,:) thetaeval = yeval(2,:)

3 Monate vor | 0

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Verifying my code for this problem, are these the right solution and graphs?
Look at the contour plot. The temperature at x = 0 should be at T_b = 50°C. This is not the case in your graphics. Maybe you int...

3 Monate vor | 0

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Optimization method based on the Nonlinear least squares as well as fmincon for the defined objective function (Non-linear function).
You can add a multiple of the vector you obtain by the below command "double(null(A))" to "estimated_T", and you will still get ...

3 Monate vor | 0

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Error in ode45 and 'Events' of a Satellite Tracking Radar Model
The "tspan" vector you provide for "ode45" has no influence on the internal time steps taken by the integrator. In zones with st...

3 Monate vor | 0

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