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Torsten


Last seen: Today Active since 2013

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Answered
Solving equation without syms
For the first equation: Build the polynomial of degree 3 in V with pencil and paper, give numerical values to S,V0,C and P and ...

alrededor de 12 horas ago | 0

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Answered
Determining the steady-state concentrations using your numerical solutions.
Set dadt,dbdt,dcdt and dddt to 0 and solve the algebraic system in a,b,c,d using fsolve, e.g.

1 día ago | 0

Answered
Make a 3D plot over a circle
r=linspace(75,365,25); phi=linspace(0,2*pi,36); [R,PHI]=meshgrid(r,phi); X=R.*cos(PHI); Y=R.*sin(PHI); Z=interp1(rm,velm,sq...

1 día ago | 0

Answered
Replace powers with a sequence
syms x c = sym2poly(expand((x-1)^3)); e = sym('e',[3,1]); c_times_e = c*e

1 día ago | 0

Answered
computing a interpolating polynomial for some function
x = linspace(-1,1,20); yfunc = @(x) 1./(1+16*x.^2); y = yfunc(x); ... or x=linspace(-1,1,20); y=1./(1+16*x.^2); ...

1 día ago | 0

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Answered
how to find the reversal matrix
B = (v.'\i.').'

2 días ago | 1

Answered
Doubt about finding the nearest values between array and a matrix
for i=1:size(Array,2) [r{i},c{i}] = find(abs(Matrix-Array(i))==min(abs(Matrix(:)-Array(i)))); end

3 días ago | 1

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Answered
Finding the last value of a difference equation
Then iterate 2-times more starting with n=1 instead of n=-1. function res = my_matlab_function(A,N) y = zeros(N+1,1) y(1)...

4 días ago | 0

Answered
Optimization with time-dependent constraint
Use "linprog" and define the 24 equalities SOC_i - (SOC_i-1 + c_i - d_i) = 0 (i=1,...24) in the matrix Aeq with SOC_1,...,SO...

4 días ago | 0

Answered
Why does 40-variable optimization array exceed maximum array size preference?
It's hard to see what MATLAB does when using the problem-based approach. I prefer the solver-based approach because it is much ...

4 días ago | 0

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Answered
Solving system of four second order ODEs
4 second-order ODEs need 8 initial conditions, not 4.

5 días ago | 1

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Answered
5x5 matrix (P) with all 25 values unknown. I have two known matrices of size 5x5 each (A1 and A2) and the relation P*A1*inv(P)=A2. How do I obtain P?
I think you could also get such P by solving the linear optimization problem min: sum_ij (eij+ + eij-) under the constraints ...

5 días ago | 0

Answered
eig return complex values
Use E = eig(A,C) instead of E = eig(inv(C)*A) or E = eig(C\A)

6 días ago | 0

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Answered
Minimize norm of the complex number array with subtraction of a variable
for ii = 1:N rng default rdc0 = 1+1i; % You add one complex value to try to minimize the resulting sum of squares ...

6 días ago | 0

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Answered
How to solve NaN when using trapz?
[num data raw] = xlsread('Flowratevel.xlsx'); for i=1:size(num,2) Num{i} = num(:,i)(~isnan(num(:,i))); end A1 = pi*Num{1...

6 días ago | 0

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Answered
How to solve 3 TDOA equations with 3 variables x,y,z
Code for symbolic solution: syms x y z x1 = 0.60; y1 = 0.00; z1 = 0.70; x2 = 0.20; y2 = 1.30; z2 = 0.70; x3 = 0.80; y3 = 1....

7 días ago | 0

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Answered
How to solve 3 TDOA equations with 3 variables x,y,z
If there are no specialized methods to solve the TDOA equations (did you take a look into the literature ?), I suggest trying s...

7 días ago | 0

Answered
how to solve system of 2 differential equation with boundaries
Rewrite your equations as a system of first-order ODEs dy(1) = y(2); dy(2) = 9*phi_A^2*y(1)/(1+y(1)+y(2)); dy(3) = y(4); dy(...

7 días ago | 0

Answered
Need help with homework (simple backwards interpolation)
Specify the extrapolation value in interp2.

8 días ago | 0

Answered
Empty Sym when using vpasolve-operator.
e = [0.05:0.05:1]; syms tp for i=1:numel(e) eqn = 900-e(i)*5.67*10^(-8)*tp^4-20*(tp-293)==0; S{i} = vpasolve(eqn,tp); e...

8 días ago | 0

Answered
How to solve for unknown function in integral equation?
One (maybe naive) approach: Choose 0=n(1)<n(2)< ... <n(K)< oo and z(1),...,z(K) Then use linsolve to solve the linear sy...

8 días ago | 0

Answered
Unable to plot iterated function system
function Modern_Art A{1} = [1;2]; n = 100; r = rand(100,1); for i=1:100 if r(i)<0.01 A{i+1} = [0 0;0 0...

8 días ago | 0

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Answered
I have an error where it says unrecognized function or variable x when using fsolve.
function main W = 1248.5*9.81; S = 17.1; list_aoa = linspace(0.0438914335842468,0.316137577406202,100); h_V_ao...

9 días ago | 0

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Answered
How to obtain the value of the matrix X in equation AXA' = B?
If you multiply out A*X*A' for a matrix of unknowns X=(x_ij) and compare the elements with those of the matrix B, you get an (in...

10 días ago | 1

Answered
How to get certain value from matrix multiplication?
https://de.mathworks.com/help/comm/ref/gflineq.html

10 días ago | 0

Answered
find the minimum objective for a given ode as boundary value problem
Vector of unknowns for fmincon: (y1,y2,y3,y4)=(a,b,c,tend) Objective for fmincon: f(a,b,c,tend) = integral_{t=0}^{tend} c*(...

11 días ago | 0

Answered
Can one help me to find Matlab coding to convert the given matrix to a symmetric matrix by rearranging rows?
Use intlinprog or bintprog to solve min: sum_{i=1}^{n} sum_{j=1}^{n} (e_ij+) + (e_ij-) under the constraints E+ - E- - (P*A -...

11 días ago | 1

Answered
Index exceeds the number of array elements. Index must not exceed 1.
z(1)=-314; v(1)=0; h=0.1; tson=10; t=0:h:tson; L=1.5; vi=0.000001; n = 100; for i=1:n Re(i)=abs(v(i))*L/vi; Cf...

11 días ago | 0

Answered
PdeModeler App Generic System of Equations are different from those in the Manual
https://de.mathworks.com/help/pde/ug/pde.pdemodel.specifycoefficients.html#bu7pwf5

11 días ago | 0

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Answered
Couette flow between two plate
Underlying equation is d^2u/dy^2 = -G/mu with G = -dp/dx = const https://en.wikipedia.org/wiki/Couette_flow function main...

12 días ago | 1

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