How can I solve a system of partial differential equations?
Use a first-order difference quotient to discretize dT_f/dz in space and use ODE15S to solve the resulting system of ordinary di...

24 dagen ago | 0

how to generate random point inside a sphere
R = 3; % radius of the sphere Xc = 4; Yc = -4; Zc = pi; % (Xc,Yc,Zc) center of the sphere rval = 2*rand(1)-1; elevation...

29 dagen ago | 0

How to find the name of a function for a known value?
Textedit the code and search for the string '0.98'.

29 dagen ago | 0

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SpecifyCoefficients for a specific PDE
https://de.mathworks.com/help/pde/examples/heat-distribution-in-a-circular-cylindrical-rod.html

29 dagen ago | 0

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R2 approximation error as in Excel
https://de.mathworks.com/help/stats/coefficient-of-determination-r-squared.html

29 dagen ago | 0

Creating new matrix from the second column of other matrices
new_matrix = [PIV_1(:,2),PIV_2(:,2),...,PIV_10918(:,2)] Quite much to write ... You should have worked with one 10918x1000x4 ...

ongeveer een maand ago | 0

Generate Independent Identically and Lognormally Distributed Random Variables
Note that mu and sigma you supply for "lognrnd" are not mean and standard deviation of the underlying lognormal distribution, bu...

ongeveer een maand ago | 0

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Why do I get the error “Dimensions of arrays being concatenated are not consistent.”?
T = [ cos(d), -sin(d)*cos(b), sin(d)*sin(b), a*cos(d); sin(d), cos(d)*cos(b), -cos(d)*sin(b), a*sin(d); 0, sin(b),...

ongeveer een maand ago | 0

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Generating random variable from certain standard deviation and mean
n = 100; x = 0.3*randn(n,1) generates 100 normally distributed random numbers with mean 0 and standard deviation 0.3.

ongeveer een maand ago | 1

How to compute numerical gradient of an unknown function in matlab Simulink?
The i'th component gi of the gradient vector g is approximately given by gi = (f(x1,...,xi+h,...,x10)-f(x1,...,xi,...,x10))/h ...

ongeveer een maand ago | 0

Having Trouble Using For-Loop Over Distributed Range with ODE45
delta1 = @(t) (t<=1200) delta0 = @(t) (t>1200) ODE = @(t,x,gamma,psi,beta) [delta1(t)*(-gamma)*x(1) + delta0(t)*psi*x(1); beta...

ongeveer een maand ago | 3

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Substitution of initial numerical values before odefunction
Use "matlabFunction" to convert every symbolic input to ODE45 into numerical function handles before calling ODE45.

ongeveer een maand ago | 0

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How do I maximise Volume of a cylinder such that its Surface Area is less than 10 using fmincon by predicting only either radius or height but not both?
Not possible. Since r and h are interdependent, "fmincon" must be able to vary both and thus predict them simultaneously. Of co...

ongeveer een maand ago | 0

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this code is for calculating the probability of attack success represent for the equation A, i need to change it to calculate the probability of attack success for the equation B:where q =[0.1 ,0.2 , 0.3, 0.4 , 0.5] and p= 1-q and Z= 6
function main q1a = [0.1 0.2 0.3 0.4 0.5]; q2a = [0.1 0.2 0.3 0.4 0.5]; z = 6; vec = zeros(1,z); for i = 1:numel(...

ongeveer een maand ago | 0

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How to fix "Index exceeds the number of array elements (1)"?
for i=1:length(L) psi0= psi(i); L0 = L(i); To=[cosd(psi0) sind(psi0) 0; -sind(psi0) cosd(psi0) 0; 0 0 1]; Tg=[To ze...

ongeveer een maand ago | 1

How to fit multivariable equation?
coeffs = [inputs, ones(size(inputs,1),1)] \ outputs

ongeveer een maand ago | 0

I need help in this question please?
y(t) = sum_{i=0}^{Inf} a_i*t^i y'(t) = sum_{i=1}^{Inf} i*a_i*t^(i-1) y''(t) = sum_{i=2}^(Inf} i*(i-1)*a_i*t^(i-2) Set y''(t)+...

ongeveer een maand ago | 0

How to calculate the (odd ,even) condition in the following Poisson distribution for p_z parameter? i need some help in the code bellow
function main p1 = 0.9; p2 = 0.8; q1 = 1-p1; q2 = 1-p2; z = 6; vec = zeros(1,z); vec(1:2:end) = q1/p1; v...

ongeveer een maand ago | 1

Lagrange Interpolating Polynomials using Matlab
You must use a fitting tool, not an interpolation tool to solve your problem. Apply "polyfit" with x-values = Generation Output...

ongeveer een maand ago | 0

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CDF of rain rate
https://stackoverflow.com/questions/36385036/how-to-make-a-cdf-from-a-histogram-in-matlab

ongeveer een maand ago | 0

How to define a variable as an integer that's equal to or greater than zero?
rest = mod(struct_idx,4); if rest == 1 ... elseif rest == 2 ... elseif rest == 3 ... elseif rest == 0 ... end

ongeveer een maand ago | 0

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Matlab code for delay differential equations
https://de.mathworks.com/help/matlab/delay-differential-equations.html

ongeveer een maand ago | 1

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How to solve this equation which contains complex number, bessel equation and its derivative?
x0 = [2; 1]; fun = @(x)[real(1i*besselj(1,complex(x(1),x(2)))-complex(x(1),x(2)).*(besselj(0,complex(x(1),x(2)))-besselj(2,...

ongeveer een maand ago | 1

Finite difference method - solving boundary conditions
y1(1) - 1.0 = 0 (y1(i+1)-2*y1(i)+y1(i-1))/dx^2 - (2*(y1(i+1)-y1(i-1))/(2*dx)/(1-x(i)) + y1(i)/(x(i)^2*(1-x(i))^2)*(y1(i)^2-1+(y...

ongeveer een maand ago | 0

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How to enforce ode15s to solve a DAEs system with some state variables limited by a range?
The solution of your problem is uniquely determined by the equations you impose - you can't impose any further conditions on the...

ongeveer 2 maanden ago | 0

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Solving boundary value problem for nonlinear differential equation using method of collocation - Gauss sites
Up to my experience, the FORTRAN code "colnew" and "colsys" developed by Ascher are still the best bvp solvers available. Searc...

ongeveer 2 maanden ago | 0

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How to solve a set of DAEs with multiple dependent differential variables
The Euler equations are not thus easy to solve. You should consult a book on numerical methods for the equations of gas dynamic...

ongeveer 2 maanden ago | 0

Boundary condition in non-linear ODE
function du = ode4(eta,u) theta = u(1); Sr = u(2); % beta dtheta = u(3); % d(theta)/dr ...

ongeveer 2 maanden ago | 1

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