Answered
How to solve this differential equation? I got ''Warning: Unable to find symbolic solution.'' error. What am I missing ?
You don't miss anything - your equation is just too complicated to have an analytical solution. You will have to use a numerica...

2 years ago | 0

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Answered
fsolve error: Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.
Include the line size((2.*x_SW(2).*dfreq_SW_vr.*w(1).*g2) + ((1./4).*x_SW(1).*nu).*(f1b.*zet_0_0 + f2b.*eta_0_0).*g1.*cos(gamm...

2 years ago | 0

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Hi All. Just wondering why answer to (i) is not 4.9e+4. an why answer to (iii) is not (9x)/2 or 4.5 x. Many thanks. Brian
For (iii), use syms x real instead of syms x

2 years ago | 1

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Overwriting the maximum function evaluation
You didn't include the structure "optim_lsq" in the call to lsqcurvefit.

2 years ago | 0

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How do you compute the product of a matrix and each column of another matrix without a for loop in MATLAB, or is this just not possible?
y = C*x

2 years ago | 0

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Answered
Operands to the logical AND (&&) and OR (||) operators must be convertible to logical scalar values. Use the ANY or ALL functions to reduce operands to logical scalar values.
if all(abs(grad_g1_val) < tol) && subs(g1, {x1, x2, x3}, x') <= 0 activeSet = [activeSet, 1]; % Constraint 1 is ac...

2 years ago | 0

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Answered
ODE45 and dsolve result difference
dydx(2)=2-2*y(2)-8*x; instead of dydx(2)=2-2*y(2)-8*y(1);

2 years ago | 1

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Answered
Intersection condition between two ellipses
I'm surprised that we get a division by zero by the below solution method if the aspect ratio of the two ellipses is equal. Bu...

2 years ago | 0

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Arrayfun with Extra Parameters
Test3 = arrayfun(f,a,b) instead of Test3 = arrayfun(@f,a,b)

2 years ago | 0

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Answered
Extract the indices based on the minimum absolute value
Maybe you mean %define the number of random numbers n = 10; %define the min and max ranges of random values stvar = [0 4]...

2 years ago | 0

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How to fit a distribution whose parameters depend on other parameters?
In this case, you must assume a parametric expression for T(z) as well (e.g. T(z) = a + b*z) and add a and b to the parameters t...

2 years ago | 0

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Solve and plot system in x and y with varying constants e and t
basically i would like to obtain on the same graph different curves in x and y for a fixed number of combinations of e and t. I...

2 years ago | 0

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sol2 = bvp4c(@bvpexam2, @bcexam2, sol);
Ibrardual() function Ibrardual Nt=0.5; Nb=0.5; Le=2; Pr=1; Alpha=[-0.2138;-0.4]; s=1; A=1; %% solution in structure form %...

2 years ago | 0

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Answered
What is the most computationally efficient factorization of a matrix A?
Prove that the matrix is positive definite and count the number of FLOPs of Cholesky compared to the other factorizations. Sect...

2 years ago | 0

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what is the error here?
The error is that the parameter "S" is not an input to function "odeBVP" and thus undefined in f =[y(2);y(3);(1/3)*D1*((y(2)^2...

2 years ago | 0

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Runge kutta giving complex numbers
It doesn't make sense to use such discontinuous input data for the solution of a differential equation. Solving a differential ...

2 years ago | 0

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How does Matlabs Symbolic Math Toolbox always finds an analytical eigendecomposition for arbitrary polynomial matrices?
For me this begs the question, is the eigenvalue polynomial from eig(...) truly analytic? What do you mean for a polynomial to ...

2 years ago | 1

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Answered
Want to understand how to implement in matlab the following differential equation?
If you know P1 over time, you don't have a differential equation, but simply an algebraic relation to determine Q: Q = (P1-P2)/...

2 years ago | 0

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Coding the Thomas algorithm for a heat and mass transfer problem
When I run the function, I get: Not enough input arguments. Error in solvePDEs (line 27) y(n) = linspace(y_span(1), y_s...

2 years ago | 1

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Answered
Mapreduce with tall array in matrix multiplication
Would this work for you ? B = ones(2,3); A = tall(ones(200,2)); values = A*B; gather(values)

2 years ago | 0

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Does pdepe accept 'Vectorized', 'on' as an option? If so, what does it do?
If you look into the documentation for "pdepe", you will find that the "Vectorized" option cannot be chosen: Cited from the doc...

2 years ago | 0

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Answered
Complex Integration in MATLAB with symbolic integration limits
Does this help ? Note that no distiction is made about the R-value. But you should keep in mind that the answer is incorrect i...

2 years ago | 0

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how i can change column vector into row vector??
Simply converting a row vector into a column vector needs the usual transpose operator which is .' You used only ' with is conju...

2 years ago | 0

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Does cummax works in a sde solver?
My question is: does here cummax works on all previous values of X(2)-X(1), or it takes it as a scalar at every iteration? It t...

2 years ago | 0

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H have a error in FDM.
F(i+1) = (F(i) + F(i+2))/2 -H(i)*(h/2)*(F(i+1)-F(i)) +(h^2)*(G(i)^2) - (h^2)*(F(i)^2) + (h^2)*(S/2)*((((i*h)+1)/2)*((F(i+...

2 years ago | 0

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Answered
Error using matlab.internal.math.interp1 Input coordinates must be real.
For some reason, the k suggested by "fminbnd" becomes complex-valued so that interpolation in function "valfunsto" is no longer ...

2 years ago | 0

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Answered
Computing Partial derivates of anonymous functions comprised of sum of standard functions
Your code works for me. Maybe you have a MATLAB version where the second argument to "diff" is only interpreted as the order of ...

2 years ago | 0

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Computing Partial derivates of anonymous functions comprised of sum of standard functions
Stay numerical in your computation and approximate the gradient of your objective function "obj" by finite-difference quotients:...

2 years ago | 0

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Answered
How do I optimize/find the minimum of a multi-variable function?
If you don't restrict your x- and y- variables to certain lower and upper bounds, the minimum of the function your get from "fit...

2 years ago | 0

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Can I use fmincon with a whole model as function?
I don't see your problem. You call "fmincon" as sol = fmincon(@fun,x0) and write a function "fun" as function obj = fun(x) ...

2 years ago | 0

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