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How to perform correct numerical integration of equations containing Bessel functions ?
I suspect you want exp(-zeta^2/(4*0.0277)) instead of exp(zeta^2/(4*0.0277)) in your integrand. And why do you add the same Bes...

2年以上前 | 0

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Trouble with fmincon - minimizing a vector
The appropriate objective is to minimize -sum(similiarityvalues.^2)

2年以上前 | 1

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Get solution for a linked multi-stage BVP
How do I model this problem? By solving it as a multipoint boundary value problem: https://uk.mathworks.com/help/matlab/math/s...

2年以上前 | 0

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Boundary Value Problem based on specific problem
x(0) = 0 gives C1 = 0, x'(0) = 0 gives C2 = 0. Thus the solution of your equation is x = 0 for all t.

2年以上前 | 1

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odeToVectorField takes forever to run
Are you sure you want to differentiate with respect to functions of t (like theta1, theta1_dot, theta2_dot) ? drn1 = diff(r1,th...

2年以上前 | 0

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Solve second-order ODE with Robin boundary condition
syms x y(x) A B C a b dy = diff(y,x); eqn = diff(x^2*dy,x)-2*y == 0; cond1 = A*dy(a)+B*y(a)/a == 0; cond2 = A*dy(b)+B*y(b)/b...

2年以上前 | 0

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I want to solve the Lyapunov equation with matlab
Use MATLAB's "lyap" or "dlyap".

2年以上前 | 0

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Is matlab able to solve a system of coupled PDE and ODE?
Setting c = 0 in "pdefun" deletes the time derivative of the respective equation and makes the equation an elliptic one. But y...

2年以上前 | 0

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graph is the not plotted as desired because of tolerance level
dydx(5) = (-t4./(1-1i.*H1)).*y(4); instead of dydx(5) = (-t4./(1-1i.*H1)).*y(3); in your function definition. I didn't look...

2年以上前 | 0

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Having trouble with lsqcurvefit for a heat transfer experiment.
The calls to lsqcurvefit must be h_freebrass = lsqcurvefit(T_free_brass2,10,x,T_free_brass) h_freecopper = lsqcurvefit(T_free_...

2年以上前 | 0

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Error using pdepe Unexpected output of PDEFUN. For this problem PDEFUN must return three column vectors of length 2
The size of "f" is 4x1 instead of 2x1 (see above). Further, if your x-mesg starts at r=0 and you choose m=2, it must hold that ...

2年以上前 | 0

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How can I plot a graph by varying two parameters a and b in system of ODE at the same time?
A = [1;2;3]; B = [2;3;4]; C = 10000; d = 2; e = 5; g = 1; tspan = [0 5]; for i = 1:numel(A) a = A(i); b = B(i);...

2年以上前 | 1

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How to find same values in a randi function
Hand = randi(13,[1,5]) arrayfun(@(i)nnz(Hand==i),1:13)

2年以上前 | 0

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how can I calculate my expression with double integration?
Maybe you mean this, but I'm not sure: D = 100; e_f = 1.88e-18; m = 9.11e-31; k_b = 1.38e-23; h_bar = 1.05e-34; ksi = 1e-9...

2年以上前 | 0

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I need to solve a system composed by four coupled equations: three ODE and one algebric non-linear equation.
You can try a differential-algebraic solver like ode15s that accepts a mixture of differential and algebraic equations by defini...

2年以上前 | 0

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fsolve with bound constraints - transformation method
Transformation and initial values are two independent problems that both have to be solved. You cannot compensate "bad" initial ...

2年以上前 | 0

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implicit numerical method: 1-D unsteady state heat transfer using finite difference method
pde() function pde() % Constants Ly = 0.0015; % Total thickness of the system (meters) T = 40; % Total s...

2年以上前 | 1

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Interpolating data to get values at specific depth
Make X and Y also 224x164x37 (just by repeating the planar profile 37 times) and use interp3 to interpolate to the depth of your...

2年以上前 | 2

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How can I find the vector that simultaneously maximizes my two functions?
Usually, you can't find a vector that maximizes both of your functions simultaneously. You can compute the pareto-front for your...

2年以上前 | 1

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Solving nonlinear system of PDE by using finite difference method for spatial and RK4 for time derivative?
You need two boundary conditions for Tap, one boundary condition for Tsg and one boundary condition for Tag. Your equation for ...

2年以上前 | 1

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PDE solve with bvp4c
Take a look here on how boundary value problems with two regions (in your case -1 to 0 and 0 to 1) have to be set up for bvp4c: ...

2年以上前 | 0

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Solve a system of nonlinear differential equations
Define the unknown functions as y(1) = F, y(2) = dF/dx, y(3) = G, y(4) = dG/dx, y(5) = H. Then the equations are dy(1)/dx = y(...

2年以上前 | 1

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I need some help to solve non-linear equation with three unknowns and three knowns with having 170 different values for one known.
M = [eta+1,Rz,-Ry;-Rz,eta+1,Rx;Ry,-Rx,eta+1]; M = repmat(M,170,1); b = []; for i = 1:170 b = [b;Xw(i)-Tx;Yw(i)-Ty;Zw(i)-Tz...

2年以上前 | 0

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How can I skip the rest of an if statement?
Also in for-loops, "break" only exits the inner structure, but the outer loop runs until the end (see below). Thus you cannot ...

2年以上前 | 0

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Error using vertcat Dimensions of arrays being concatenated are not consistent..
Most probably: second_derivative = diff([0, diff(Ida_normalized(i:window_end))]); instead of second_derivative = diff([0; dif...

2年以上前 | 1

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Surface plot doesn't correspond to optimization solution
The problem is now, when I select a point randomly in the surface plot, and then calibrate the model for these values, I do not ...

2年以上前 | 0

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Solving an equation with symbolic matrix
https://uk.mathworks.com/matlabcentral/answers/1918100-error-using-solve-with-symmatrix-equation

2年以上前 | 1

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A group of 12 people all roll a pair of dice 12 times, how often does each person roll a total number that is greater than or equal to 7?
In my opinion, it should be roll1=randi(6,12); roll2=randi(6,12); total=roll1+roll2; GT7 = total>=7; totalGT7 = sum(GT7,1);...

2年以上前 | 1

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error in for loop
u(j-3) is only defined for j>=4, u(j+3) is only defined for j<=length(R)-3. Similar restrictions hold for the other indices. Thu...

2年以上前 | 0

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I'm suppose to plot the response of the system but i'm getting wrong values
alpha is a constant , and this is the value of it , I doubt that the rate of change at t=0 for x(5) should be 2.55e17 as you g...

2年以上前 | 0