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How to solve symbolic and trigonometric equations simultaneous, two unknowns
Your equation has several solution, as already demonstrated in a previous post. Here is one of them: syms alpha gamma %R d %...

4 years ago | 0

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set Anonymous function through a series of matrix for "lsqcurvefit" or "lsqnonlin"
x0 = [0.3,0.4]; F = @(x,k) arrayfun(@(k)[2, 2, exp(k*x(1)), exp(k*x(2))] * [1; k; -1; -1],k) % same as above equation, but fro...

4 years ago | 0

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Answered
Plotting an integral function
L=1.5; h=.2; s=.75*L; tbar=1; y=0; icount = 0; for xbar=-1.5:.1:1.5 icount = icount + 1; if xbar>-L & s>xbar ...

4 years ago | 1

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I tried Euler's method and RK4 method but I'm getting different results. Please can someone help
%global x_vec dx k %clear %clc %clear all %%%% du/dt = d^2u/dx^2; u is f(x,t) %%%% DFM: (u(x, t+dt) -u(x, t))/dt = k*(u...

4 years ago | 0

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"Trapz" function gives result different than what I calculate by hand
For x = y = [1 2 3 4 5], I = (1+2)/2 + (2+3)/2 + (3+4)/2 + (4+5)/2 = 24/2 = 12.

4 years ago | 1

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ODE15s with non-constant Jacobian
JacFun = J(u_int, deltaZ, Nz, cFeed); options = odeset( 'Jacobian' , @(t,x)JacFun(t, x, u_int, deltaZ, Nz, cFeed), 'RelTol',1e-...

4 years ago | 1

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Answered
Integration of the expected value
b = 1; N = 2000000; for i = 1:N p(i) = b*rand; pe(i) = p(i) + (b-p(i))*rand; p2(i) = p(i) + pe(i); end ecdf(p...

4 years ago | 1

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Answered
Why do I get the wrong value when I increase N?
a = 0; % Lower Boundary b = 10; % Upper Boundary fun = @(x)sin(pi*x/10); % Function zeta = [-sqrt(3/5) 0 sqrt(3/5)]; % absci...

4 years ago | 0

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Trouble with least squares fit to 3D ODE model with 2D observed data
[~,Sv] = ode45(@(t,y) growth(t,y),t,y0); instead of Sv = ode45(@(t,y) growth(t,y),t,y0);

4 years ago | 0

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How can I change the definition of x to find the value of y(3.5112)( i mean y(x1)) for this question ?
I don't know if it helps: %%main func clear all; close all; clf; clc; % Define the function x = linspace(-10,10,100); ...

4 years ago | 0

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Trouble defining a set of parameters while using ode45 to solve a system of differential equations
This page should help you: https://de.mathworks.com/help/matlab/math/ode-event-location.html

4 years ago | 0

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Finding the turning point on a curve
v = [-0.000499915992890149 -0.00136716055731299 -0.00312202879147695 -0.00415143850349407 -0.003723995799058...

4 years ago | 0

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Answered
how to substitute a symbolic differential equation?
syms x(t) y(t) lambda h = 2*diff(x,t,2) + (diff(y,t))^2; xtt = diff(x,t,2); yt = diff(y,t); h_subs = subs(h,[xtt,yt],[lambda...

4 years ago | 0

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How to pre-allocate a double for following script ?
What about syncat = zeros(100000,2) ?

4 years ago | 1

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Getting a system of equations and the using ODE45
fun = @(x) Xi.'*[1;x(1);x(2);x(3);x(1)^2;x(1)*x(2);x(1)*x(3);x(2)^2;x(2)*x(3);x(3)^2;x(1)^3;x(1)^2*x(2);x(1)^2*x(3);x(1)*x(2)^2;...

4 years ago | 1

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Answered
i need to find the optimize values of R for a values in an interval but R values are in form of the root of the equation; how to solve this sir? for simple equation it was ok.
I think this is the safest way: syms R a p = -282091600255531819/9878934086330590709531986654911361482361187039433493704830155...

4 years ago | 0

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Answered
Index in position 3 exceeds array bounds (must not exceed 1)
"orph" has dimension 1 x 20000 because you overwrite the image by the command orph = [i,j]. Then you try to access orph(:,:,2)...

4 years ago | 1

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i need to find the optimize values of R for a values in an interval but R values are in form of the root of the equation; how to solve this sir? for simple equation it was ok.
Try "fmincon" for the problem min: R s.c. f(R,a) = 0 (f is the complete expression between "t=solve(" and "==0,R)) a_left <...

4 years ago | 0

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Error using cat Dimensions of arrays being concatenated are not consistent.
Xtrain = cat(2,Xtrain,smat.'); would work, I guess.

4 years ago | 0

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How to find L from the given code?
lags = 0.6; k1 = 3; k_1 = 1; k2 = 2.5; k3 = 1; k_3 = 1; k4 = 2; k5 = 1; E1 = 1; E2 = 2; K1 = (k_1+k2)/k1; K2 = (k_3+k...

4 years ago | 1

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Answered
i have to plot the percentage of heads by the times token is trowed times, in a game of head or tail, but a need help for doing that. What can I use in my plot?
N = 500; x=rand(1,N); for i = 1:length(x) if x(i) < 0.5 x(i) = 1; % cara else x(i) = 0; % coroa ...

4 years ago | 0

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Answered
ode15s solver produces wrong solution
t0 = 0; % initial time tf = 1; % final time nt = 20; % number of output times xl = 0; % left point xr = 1; % right point nx...

4 years ago | 0

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Answered
How to store n iterations of randomly generated matrices
n = 10 ; bounds = [1 100] ; %interval over which the random number generator will produce values randA = zeros(3,3); randA_al...

4 years ago | 0

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Numerical answer to Partial derivative of Hopfield-style Energy in symbolic expression
p is (4x1), not (16x1). And keep r_mat as matrix, then E = -0.5*p.'*r_mat*p - c.'*p ( r_mat can be assumed symmetric ). By...

4 years ago | 0

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Error from ode15s
psi = 0.63; psip = 0.27; L = 150e-6; Ts = 60; k = 0.00158; q0 = 4.62e3; C0 =1.03; gama = 5021.8; Jw = 8.5e-6; a = psi*...

4 years ago | 0

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Array indices must be positive integers or logical values.
e = exp(-SNR_index.^2./2) SNR_index is undefined. compute_the_Q = integral(@(SNR_index) (1/sqrt(2*pi)).*e, SNR_index,Inf,'Arra...

4 years ago | 0

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How can I simulate Buffon's needle on MATLAB?
https://simonensemble.github.io/2018-04/buffon

4 years ago | 0

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Solve Three non-linear equations for 3 variables system
You might want to try a numerical solver, but the two I tested also didn't succeed. fun = @(A,B,C)[72000-(B*4000)/(log(A*4000)-...

4 years ago | 0

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Coupled ODE using ODE15s with multiple outputs
When communicating with ODE15S, the solution must be treated as one vector of size 200, not as two vectors of size 100. E.g. f...

4 years ago | 0

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Answered
Is it possible to (non-linear) minimize x^y by choosing both x and y?
fun = @(x) x(1)^sqrt(x(2)); lb = [1.01,1.01]; ub = [100,2]; x0 = [1.01,1.01]; sol = fmincon(fun,x0,[],[],[],[],lb,ub,@nonlco...

4 years ago | 0