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# Torsten

Last seen: Today Active since 2013

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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...

16 hours ago | 0

Calculation of the center of mass of a cone

16 hours ago | 0

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...

16 hours ago | 0

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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.

17 hours ago | 0

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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) ...

17 hours ago | 0

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)

18 hours ago | 0

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...

22 hours ago | 1

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', '...

22 hours ago | 0

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...

22 hours ago | 1

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 ...

22 hours ago | 1

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...

22 hours ago | 0

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)

1 day ago | 0

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(...

1 day ago | 0

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) ...

1 day ago | 0

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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 =...

1 day ago | 0

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 ...

1 day ago | 0

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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...

2 days ago | 0

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...

2 days ago | 0

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)

2 days ago | 0

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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...

2 days ago | 0

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*...

3 days ago | 0

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...

3 days ago | 0

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...

3 days ago | 0

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

3 days ago | 0

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

3 days ago | 0

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...

3 days ago | 0

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)*...

3 days ago | 0

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...

3 days ago | 0

How to add integral in a integral function
format long integral(@(x)sin(integral(@(a)sin(a),0,x)),0,1,'ArrayValued',true) integral(@(x)sin(1-cos(x)),0,1)

4 days ago | 0

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