Community Profile

Torsten

2,540 total contributions since 2013

View details...

Contributions in
View by

Integrate for a specific period of time
t=0:.01:10; x = zeros(numel(t)); x(1) = 1; fun_xdot = @(t,x) -2*(x^3) + sin(0.5*t)*x; for i = 1:numel(t)-1 x(i+1) = x(i...

1 month ago | 0

| accepted

Why does fsolve seem not iterate towards the solution?
k = 0.1007; rZ = 12.6518; Rs = 0.164; Cmax = 7.0e-11; W = 1.704e8; iZ = 14.5273; Ls = 1.1e-7; a1 = (k/1000)^2*(rZ-Rs); ...

1 month ago | 0

| accepted

I am getting this error "Index in position 1 is invalid. Array indices must be positive integers or logical values." Kindly help me clear this.
i and j are not defined at this line of your code ; they are first introduced one line later.

1 month ago | 0

Finding Linear regression equation
x = [65 65 62 67 69 65 61 67]; y = [105 125 110 120 140 135 95 130]; X = [ones(numel(x),1),x.']; p = X\(y.'); b = p(1) m ...

1 month ago | 0

Non linear least squares for a system of equations
fun = @(z)[z(1)^0.5*Ydata+z(2)-X1data,... z(1)^0.1*Ydata+z(2)-X2data,... z(1)^0.15*Ydata+z(2)-X3data]; ...

1 month ago | 1

| accepted

How to iterate with fsolve to find Mach number
function main pt2pinf = [1.9, 2.7, 3.5, 4.3, 5.1, 5.9, 6.7, 7.5, 27.5, 47.5, 67.5 ,87.5 ,107.5,127.5, 147.5, 200, 252.5, 305,...

1 month ago | 0

| accepted

Setting of mass matrix
options = odeset('RelTol',1e-9,'AbsTol',1e-9*ones(608,1),'Mass', @(t,y)diag([ones(1,604) sin(t) 1 1 0])); or options = odeset(...

1 month ago | 2

How do I declare and iterate a variable in an ODE driver file?
yold = -Inf; Ssnh_in_1 = 1; [t,y]=ode15s(@(t,y)pha_cont(t,y,Ssnh_in_1),[0,15],y0); ynew = y(end,3); while yold < ynew Ssn...

1 month ago | 0

| accepted

Ode45 solves an equation that containing a definite integral term
function main a = ...; b = ...; c = ...; d = ...; u0 = 1; usol = fzero(@(u)fun(u,a,b,c,d),u0); fun_ode = @...

1 month ago | 1

Problem with jacobiSN function
I suggest you follow the steps suggested under https://de.mathworks.com/help/matlab/matlab_prog/calling-functions.html

1 month ago | 0

Weighted linear combination between vectors
weights = [0.25 0.25 0.25 0.25]; C = weights(1)*W(:,1) + weights(2)*W(:,2) + weights(3)*W(:,3) + weights(4)*W(:,4);

1 month ago | 1

Can you help me please !
function main tspan=[0 5]; y0=[0;100;0;10]; [t,y]=ode45(@khidonghoc,tspan,y0); plot(t,y(:,1),t,y(:,3)) hold on;gr...

1 month ago | 1

| accepted

How do at write the equation
f = x.^2.*sin(x*pi)

1 month ago | 0

| accepted

Plotting the zeros of jacobi polynomials
I'd use https://de.mathworks.com/help/symbolic/jacobip.html :-)

1 month ago | 0

Solving BVP for DAE in Matlab
MATLAB has no built-in solver for boundary value differential-algebraic equations. COLDAE is a very good solver, but it's writt...

1 month ago | 1

| accepted

t = -511*0.005:0.005:512*0.005; u_1 = 3/2*(110*sinc(110*t)-60*sinc(60*t));

2 months ago | 2

Using the function fmincon
[x] = fmincon (@FUNCTION,coef,[],[],Aeq,beq);

2 months ago | 0

| accepted

pdepe is not suited to solve pdes without second-order spatial derivative. You will have to discretize the above equation on yo...

2 months ago | 0

ODE solver problem with input
function main [t,y] = ode45(@Flug_DGL,[1,300],[0;0]); plot(t,y(:,1)); end function ypunktpunkt = Flug_DGL(t,y) u ...

2 months ago | 0

How to calculate the probabilistic constraints in Matlab?
a1+a2+a3 = norminv(0.9,mu,sigma) https://de.mathworks.com/help/stats/norminv.html

2 months ago | 0

| accepted

Solve systems of linear equations Ax = B for x
https://en.wikipedia.org/wiki/Cramer%27s_rule

2 months ago | 0

system on inequations of a problem in mathematic
The coloured region is defined by three inequalities: y >= (x-x_A)/(x_B-x_A)*y_B+(x-x_B)/(x_A-x_B)*y_A y >= (x-x_A)/(x_D-x_A)*...

2 months ago | 1

| accepted

Why do my coeffvalues not produce a sensible result?
If you use the 'Normalize','on' fitting option, your polynomial has powers of (x-meanx)/stdx and (y-meany)/stdy instead of x and...

2 months ago | 0

| accepted

solving a system of nonlinear equations in terms of parameter (essentially rearrangement)
Does this work ? syms a b c k t x eqn = x == a + (((c - k + (1/3)*(((c - k + (1/3)*t*(1-a-b)*(3+b-a) + t*(2*(1-b-x)^2 - (x-a)...

2 months ago | 0

estimation of parameters using lsqnonlin
1. p= lsqnonlin(@(p) interest(p),p0) Use p=lsqnonlin(@(p)interest(p,t,c1meas,c2meas,c3meas,c4meas,c5meas),p0) instead. 2. ...

2 months ago | 0

| accepted

How to fix: Index exceeds matrix dimensions
The for-loop increases i automatically. Thus remove the line "i=i+1".

2 months ago | 0

simple integration calculation to find the area ?
value_integral = trapz(T,V)

2 months ago | 0

Matrix dimension do not agree when solving a singular bvp using bvp4c
Your boundary conditions can not be handled by bvp4c: You prescribe two times that y(2)=0 at the left boundary point and you gi...

2 months ago | 0

Trying to solve a definite integral but wont give numerical solution
Q=150; k=1.49; n=0.02; So=0.0048; b=3; g=32.2; x1=0; y1=3; %x2=200; h=20; x2=200; f_xy=@(y)(So-((Q*n)./(k*b*(y.^(5/3)...

2 months ago | 1

| accepted