Answered
Extracting symbolic values from symbolic matrix
syms t q2(t) q3(t) a1 a2 n1 = [a1*q3(t);a2*sin(q2(t));0]; n1(2,1) % extract element (2,1) n1(2,:) % extract complete 2nd ...

3 years ago | 0

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Answered
Why du/dx obtained from excel and Matlab gives different results?
If the X grid is equidistant, dudx = gradient(U,X(2)-X(1))

3 years ago | 0

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Desorption-Fixed bed- Initial conditions
Then set c0 = cFeed*ones(n,1) c0(1) = 0.0; q0 = qFeed*ones(n,1) as initial and boundary conditions of the desorption, if thi...

3 years ago | 0

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Answered
plot a function wit cos
f=(0:10); %f0=5*10^9; c=(3*10^8); t=5*10^9; w=2*pi*f; wt=w*t; k=(wt/c); z=(0.75:30); r12=0.29; %x=0.094*cos*(k*z); y=0...

3 years ago | 0

Answered
How to fix error in my DAE program?
The call to ode15s is incorrect: [t,y] = ode15s(@(t,y) reduced21(t,y,T_a),tspan,y0); instead of [t,y,ydot] = ode15s(@(t,y,ydo...

3 years ago | 0

Answered
How to generate matrix from iterations?
V1 =[0 20 60 80 100]; V2 =[20 60 80 100]; itermax = 10; for i = 1:numel(V1) v1 = V1(i); for j = 1:numel(V2) ...

3 years ago | 0

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how could i plot x^2+(y-x^3/2)^2=1 ?
fun = @(x,y)x.^2+(y-x.^3/2).^2-1; fimplicit(fun)

3 years ago | 0

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How to solve PDE with two regions
Yes. Choose "a" as a grid point for pdepe. Then you can solve your system as one partial differential equation for C_B by addin...

3 years ago | 0

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Unable to meet the tolerance without using more than 1666 mesh points.
Seems to work (see above).

3 years ago | 0

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Answered
too many input arguments Fmincon
parametersV = fmincon(objFun,parametersV,[],[],[],[],[],[],[],options); instead of parametersV = fmincon(objFun,parametersV,[]...

3 years ago | 0

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Answered
The control parameters of MILP
Read about "options" under https://de.mathworks.com/help/optim/ug/intlinprog.html

3 years ago | 0

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Answered
Change the format of output answers of two variable in two equations
T_surf_Max = double(S.T_surf(1)) T_o_Max = double(S.T_o(1))

3 years ago | 0

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Answered
Solution of Fick's Second Law of Diffusion Equation
Then discretize d^2C/dx^2, d^2C/dy^2 and d^2C/dz^2 and use the method of lines to integrate dC(i,j,k)/dt = D*((C(i+1,j,k)-2*C(i...

3 years ago | 1

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Answered
Struggling to formulate ODEs in matlab for two point boundary value problem using bvp4c
To get a feeling for your system, I'd start with equation (7) and ode45 as integrator. Assume hydrostatic pressure at the inle...

3 years ago | 0

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Answered
How to break the infeasibility of solution for the function linprog?
[x,fval,exitflag,output] = linprog(___) if exitflag > 0 % linprog was successful take action 1 else % linp...

3 years ago | 2

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Answered
Minimization of two simultaneous ODES with shared parameters
https://de.mathworks.com/matlabcentral/answers/43439-monod-kinetics-and-curve-fitting

3 years ago | 0

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Answered
Error When Using ODE45 to solve symbolic ODE Equation : Too many input arguments.
s = 1; N_s = 3e15; V = 16.7; S = 4.6; tao_p = 3.6; tao_0 = 10e-13; v=4.82e20; R=8.31; T=295; Ed = 25; a = ((s*v*tao_0)...

3 years ago | 1

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Answered
I am unable to understand the error messages and correct the errors.Can anyone correct my code?
syms x y(x) E=207e9; P=1000; m=2; n=2; Ix=(pi/(1024*m^4))*(x^2-4*m*n)^4; I1x=diff(Ix); I2x=diff(I1x); eqn = diff(y,x,4) ...

3 years ago | 0

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How can I plot a graph according to the results
clc clear %Newton method func = @(x,y) 10*x.^2 - 4*x.*y + 7*y.^2 - 4*sqrt(5)*(5*x-y) - 16 ; e = 0.01; i=0; n=0; b =...

3 years ago | 0

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Answered
I want to plot 100 graph for T vs abs(r) for different initial condition and therefore I wrote this code, but it doesn't plotting any graph please help mem in this code.
ti = 0; tf = 1E-8; tspan=[ti tf]; KC = 2E-6; hold on for j = 1:100 y0= [(1e-2)*rand(2,1); ((-3.14).*rand(1,1) + (3.14).*ra...

3 years ago | 0

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Answered
How to save a matrix into a number?
max2min = [ 4 3 2 1]; min2max = fliplr(max2min); max2min = str2double(sprintf('%d',max2min)); min2max = str2double(spri...

3 years ago | 1

Answered
converting equation into multiple of two matrix
https://de.mathworks.com/help/symbolic/sym.equationstomatrix.html

3 years ago | 0

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Answered
Inequality constraint cause infeasible results in NMPC
Your constraints say that a number should be >= -5000 (Min/Max constraint) and that it should be <= -5000 (U(2)+5000). That's ha...

3 years ago | 0

Answered
How do i solve differential equation 2nd oder simbolically and numerically?
syms t y(t) sigma(t) eqn_diff = diff(y,t,2)+3*diff(y,t)+y(t)-2*sigma(t)==0; ysol(t) = dsolve(eqn_diff); var = symvar(ysol) e...

3 years ago | 1

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Answered
How to solve method of lines on one-dimensional heat equation using Euler's method?
% Parameters k = 0.5; % Evaluate BC dx = 0.01; x = 0:dx:1; dt = 0.0001; t = 0:dt:0.5; h = 1/(length(x)-1) ; %step size ...

3 years ago | 0

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Answered
I need help to make graphs please
See above. I added four lines to your code to plot the results and changed the line flux(index)=fluxp+fluxe0+fluxe1+fluxe2; to...

3 years ago | 1

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Answered
The proper way to sample 3 normally or lognormal distributed variables added up to 1
You can define a common probability distribution of the three variables on the triangle x + y + z = 1, x, y, z >= 0 but this c...

3 years ago | 0

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How can I constrcut this matrix for a problem?
If x = [x0,x1,...,xn] is an 1x(n+1) row vector, you could use M = zeros(n+1); for i = 1:n+1 M(i,:) = psi(x(1:n+1)-x(i)); ...

3 years ago | 0

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Answered
Are the algorithms used in mldivide direct solvers?
Are the algorithms used by "mldivide" for any input direct solvers (not matter if (not) sparse, (not) symmetric, (not) banded et...

3 years ago | 0

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how to write an equation the it is function of itself (solar cell current equation)
I guess you want to solve for J ? Then define fun_J = @(J) J - (J_PH - J0*(exp(q*(V+J*R_S)/(k_B*T))-1)-(V+J*R_S)/R_SH) and u...

3 years ago | 0