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Need some change in the present Analytical solution code which I'm unable
syms x F1(x) G1(x) H1(x) n fw h Nt = 0.5; Nb = 0.5; Pr = 1; Le = 2; DF = diff(F1,x); eq1 = diff(F1,x,3) + diff(F1,x,2) == 0; ...

2 years ago | 0

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Answered
Please help with fzero function . Thanks
Convert dh_CO2 and dh_H2O from symbolic functions into function handles by using "matlabFunction". After this, they can be use...

2 years ago | 1

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Don't know how to put set of numbers in equation
Replace N = a / (sqrt(1-e2 * sin(fi)^2))^3/2 by N = a ./ (sqrt(1-e2 * sin(fi).^2)).^3/2 For an explanation, I suggest readin...

2 years ago | 0

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Index exceeds the number of array elements error
y(i-N:i-1) is a vector of length N z(i-N:i-N+M) is a vector of length M+1 y(i) is a single value of length 1 How do you imagi...

2 years ago | 0

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Fsolve 19 state variables with matching dimensions
Rename F in this assignment: F = Fin + Fr F is reserved for the 19-element function vector that you return to fsolve.

2 years ago | 0

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Answered
Please help, I have no idea how to do this integral in matlab
The integral seems to exist for those values of theta0 with cos(theta0) ~= 0, thus theta0 ~= (2*k+1)*pi/2 for k in Z. In this c...

2 years ago | 1

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Answered
Simplify symbolic division abs(Z)/Z
Use z*z' instead of abs(z)^2: syms z u = z*z'/z

2 years ago | 0

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Why is ode45 failing to solve this system of ODEs?
Your matrix L has 9162 NaN values. This is most probably caused by the division by (x+1) which is problematic for the problem b...

2 years ago | 1

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Answered
Store Values in Array per Loop iteration issues
Replace [i, ~] = find(Strain < 0.01 | Strain > 0.15); Strain(i, :) = []; by [j, ~] = find(Strain < 0.01 | Strain > 0.15); S...

2 years ago | 0

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Answered
I need to pursue the developement of a variable within a function, but I don't know how.
[t_num,x_num]=ode15s(@DGL,tspan,q0); C11_num = c_m+c_a*sin(om*x_num(:,1));

2 years ago | 1

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Answered
Im trying you solve the component mass balance and energy balance equations for an adsorption system. Im getting some exponential growth in the plots.
Use Upwind Differencing for the convection terms: dTdz(2:n) = (T(2:n)-T(1:n-1))/h; dJdz(2:n) = (J(2:n)-J(1:n-1))/h...

2 years ago | 0

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Answered
Error using bvp4c Unable to solve the collocation equations -- a singular Jacobian encountered. Error in MHDI_ori (line 54) sol = bvp4c (@OdeBVP, @OdeBC, solinit, options
You say you want to have yb(2) - R = 0 and yb(2) - 1 = 0 at the same time as boundary conditions. This is not possible.

2 years ago | 1

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Answered
Error with 3D interpolation: Interpolation requires at least two sample points for each grid dimension
VsGrid = csvread('3d_Vs_utm_samplefile.csv'); X = VsGrid(:,1); % UTM X Y = VsGrid(:,2); % UTM Y Z = VsGrid(:,3); % Depth V =...

2 years ago | 0

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Answered
Where to find Hash Sums of Matlab Downloads?
Does this help ? https://codesigningstore.com/how-to-check-file-checksum https://uk.mathworks.com/matlabcentral/answers/540626...

2 years ago | 0

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How do I generate a random number vector composed of just 1 and -1
s = -1 + 2*randi([0 1],100,1) nnz(s==-1) 100-nnz(s==-1)

2 years ago | 1

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How can I plot graph in this relationship?
s=0; hold on for j=1:1:10 s=s+j; disp(['j = ', num2str(j)] ); disp(['s = ', num2str(s)] ); plot(j,s,...

2 years ago | 0

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Array Problem How can I unpack an array? why the firt element pf my array is always 0?
We don't know how you call the function - so we cannot predict I1, I2 and I3. To your second question: I = [3 5 -6]; [I1,I2,I...

2 years ago | 0

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Integrate pressure over area, from dataset points
Maybe you want to get mean pressure over the face. In this case, divide "sol" by area = pi*(5^2-1^2) as done below. x = load("x...

2 years ago | 1

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Answered
Why do I have an error with minus sign
There is a minus sign in front of d^2M/dx^2 which is difficult to see. So everything is ok: f_0*(x/L)*(1-(x/L)) = -(f_0*x*((x/L...

2 years ago | 1

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Out of memory - dsolve 3rd order system
Does this one work better ? syms t y1(t) y2(t) y3(t) f = 10*exp(-t); eqn1 = diff(y1) == y2; eqn2 = diff(y2) == y3; eqn3 = d...

2 years ago | 0

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Solve these unkowns x and y using these 2 simultaneous equations
I think you want to use sind and cosd instead of sin and cos. This is a linear system of equations in m3R3L3 and m4R4L4. You kn...

2 years ago | 0

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How do I include or make a discrete variable for an optimization problrm?
Make a loop over the 4*4*3*3 = 144 possible combinations of x1,x2,x3 and x4 and only optimize with respect to x5, x6 and x7. In...

2 years ago | 0

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I want to solve these 2 simultaneous equations to get x and y
syms x y equ1 = 73*sind(0)+92*sind(200)+87*sind(x)+65*sind(y) == 0; equ2 = 73*cosd(0)+92*cosd(200)+87*cosd(x)+65*cosd(y) == ...

2 years ago | 0

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Answered
i was calculate using gauss jacobi method with 4x4 matrice, why does NaN appear? what should i do?
A(2,2) equals 0, but you divide by 0. What is H ? clc; A=[1 3 1 -1; 2 0 1 1; 0 -1 4 1; 0 1 1 -5]; A=[A(2,:);A(1,...

2 years ago | 0

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Index in position 2 exceeds array bounds (must not exceed 25).
Without seeing your data, I'd speculate that spec001 has only 25 columns, but that you try to address columns up to the index 20...

2 years ago | 0

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Problem with time plot from partial derivative equation solved by method of lines
It's "Conversion", not "Convertion". And setting a boundary condition at z = L is incorrect because you only have convection, n...

2 years ago | 0

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How do I define piecewise constant function in for loop?
Give the correct values to the arrays "left_limit_of_ith_interval" and "right_limit_of_ith_interval" in the following code: lef...

2 years ago | 2

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Answered
Runge-Kutta 4th Order on a 2nd Order ODE
Comparing with a MATLAB integrator, the results look ok. I don't know how you derived that "the value of k11 shoud be -0.06 bu...

2 years ago | 0

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Answered
Changing ode solver tolerances on the fly
Is it possible to change (relax) the values of the "Absolute tolerance", Relative Tolerance" on the fly just for the "problem" t...

2 years ago | 1

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Saving of state just before nonconvergence of ode solvers
The stepsize before the solver exists usually becomes small. So if you choose "tspan" in the call to the ode integrator as a 2-e...

2 years ago | 0

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