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Solving a Delay Differential Qquations that involves a mass matrix
Write out your system and you will find that x3 = x6 = x7 = x8 = x9 = 0 and you are left with the equations x1(t) = sin(2*pi*...

mehr als 3 Jahre vor | 0

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I have differnt coodinate after use fmincon
x0=[0 0]; lowerbound =[-1 -1]; upperbound = [1 1]; sol = fmincon(@distance,x0,[1 1],2,[],[],lowerbound,upperbound) functi...

mehr als 3 Jahre vor | 0

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How to plot the diffusion curve for different timesteps?
Save C in the loop for the values of t where you want to plot the curves. You should get a matrix like C(ntimes,nx). Then outsi...

mehr als 3 Jahre vor | 2

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Calculation of the center of mass of a cone
https://de.mathworks.com/matlabcentral/answers/1849928-how-can-i-find-solid-cone-center-of-mass?s_tid=srchtitle

mehr als 3 Jahre vor | 0

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Create a function that will return the cdf at any given point to implement the bisection code.
syms c x real f = c*exp(-x.^3); cnum = solve(int(f,x,0,Inf)==1,c); f = subs(f,c,cnum); F = int(f,0,x); F = matlabFunction(F...

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Using the right values for the variables, function gives a completely wrong answer
You forgot that 17.523 is multiplied by pi in the calculation of L.

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I am trying to code a solution to blasius eq using Runge kutta 4, help please.
clear all; clc; % 3 First order ODE´S from Blasius Eq % dF/deta = G % dG/deta = H % dH/deta = -0.5*F*H fF=@(eta,F,G,H) ...

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How to determine the absolute value of a complex exponential function containing a symbolic variable?
syms omega t real syms I0 positive I = I0*exp(1i*omega*t); abs(I)

mehr als 3 Jahre vor | 0

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Second degree differential equation
The example Solve Nonstiff Equation under https://de.mathworks.com/help/matlab/ref/ode45.html explains in detail how to proc...

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Unable to perform assignment because the size of the left side is 1800-by-1 and the size of the right side is 4872-by-1.
Anything unclear about the error message ? rxBits has only 1800 rows, but qamdemod(rcomb, 2^bitsinreceiver, 'OutputType', '...

mehr als 3 Jahre vor | 0

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3D cylinder code debugging
zSC_lid is an 1 x nNodes vector: zSC_lid = repmat([0, hSC], 1, nNodes); Thus it has only one row. But you reference the secon...

mehr als 3 Jahre vor | 1

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Different output for find(X) and find(X<5)
find(X) lists the array elements of the double array X that are not equal 0. find(X>0) lists the array elements of the logical ...

mehr als 3 Jahre vor | 1

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the code print -inf in TT matrix. Please anyone helps
Your value of 1 for delta_t violates the CFL condition for stability of the explicit Euler scheme. Choose a value that satisfie...

mehr als 3 Jahre vor | 0

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how to derivate an equation of x and y without taking any variable constant?
You mean assuming y = y(x) ? syms y(x) f = y-x*y-sin(y) == 0; df = diff(f,x)

mehr als 3 Jahre vor | 1

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How to solve for gamma
format long dbs=5.3e-10; das=1.01e-9; cb=4e3; ca=1e3; x0 =0; options = optimset('TolX',1e-14,'TolFun',1e-14); x = fsolve(...

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Help solving system of triq equations
%Input Linkage lengths d=11.875; a=2.5; b=11.875; c=3.75; r5=5; r6=6; r7=7; r8=8; L1Theta = zeros(30,4); L1Theta(:,2) ...

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i need to find the displacement for the given values
syms p E = 3*10^4; v = 0.29; a = 39; b = 2*a; d = 1; A = pi/4; I = (pi/64)*d^2; G = E/(2*(1+v)); m =...

mehr als 3 Jahre vor | 0

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How to initialize number of iteration?
A_100_iteration = cell(51,1); Result_100_iteration = cell(51,1); for ib = 1:51 B(1) = (ib-1)*20; for n = 1:100 ...

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I'm trying to write a matlab function to solve RK4 and store it in my computer to be called when needed.
If you call RK4 correctly, it will work. syms y(x) dy_dx(x) dy_dx(x) = x + y(x); x_1 = 0; y_1 = 1; x_end = 1; h_step = 0.0...

mehr als 3 Jahre vor | 0

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error: Index in position 2 exceeds array bounds (must not exceed 31).
Note that I had to make changes to the boundary values and your loop ! Compare with your old code to see the errors you made. c...

mehr als 3 Jahre vor | 0

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function handle as array
M = rand(4,4); P_initial = rand(4,1); P = @(t) mtimes(expm(t.*M),P_initial); P(0) g = @(a,x)a(x); g(P(0),1)

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What does norm function indicate ?
From the MATLAB documentation: n = norm(X) returns the 2-norm or maximum singular value of matrix X, which is approximately max...

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My code is giving me a straight line for values of N other than 5
I'm quite sure that the 0.5 has to be taken out of the symsum: syms k N integer syms t y = 0.5 + symsum((cos(k*pi)-1)*(2/((k*...

mehr als 3 Jahre vor | 0

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Numerically integrate a time dependent differential equation
bP = 1; Te = 1; K = 1; t0 = 1; ti = 24; CDF = @(x)integral(@(t) 1/t0*exp(-bP./(Te^4+K*(307.59-190.96*(log(t/24)).^0.24)).^0...

mehr als 3 Jahre vor | 0

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Cant take the derivative of this plot...
m = 1; b = 2; k = 10; tnum = linspace(0,7,175); xlabel('0'); syms s F=1/(m*s^3+b*s^2+k*s); f=ilaplace(F); df=diff(f); v...

mehr als 3 Jahre vor | 0

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Could you please provide script to perform process described below. Many thanks in advance
A = rand(7) A = A(:,4) writematrix(A, 'A.txt')

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Error message when trying to plot
T = K ./ sqrt(2*pi*w); instead of T=(K/(sqrt(2*pi*w)));

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Multiple boundary conditions with two separate intervals
To use bvp4c, the two intervals have to be connected. Thus in your case, it's not applicable (or only with big effort). syms y1...

mehr als 3 Jahre vor | 0

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how to plot a periodic function?
a = 3.2; t1 = 5; t2 = 7; t3 = 12; t4 = 17; fun = @(x) a*(x>=0 & x<=t1) + (-a/(t2-t1)*(x-t2)).*(x>t1 & x<=t2) + (-a/(t3-t2)*...

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How can I solve coupled nonlinear hyperbolic equations?
CLAWPACK available under https://www.clawpack.org/ is an excellent solver for hyperbolic systems of differential equations. A...

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