Réponse apportée
euler method for solving system of ODE's 1st order
Simple Euler inaccurate for large step size. Reduce step size as in following and see if you get the output you expect: a=0; %...

environ 5 ans il y a | 1

Réponse apportée
How to stop ODE(R4K) function when the value is close to 0?
Have you tried replacing u_p(i+1)=u_p(i)+h/6*(k1u_p+ 2*k2u_p + 2*k3u_p +k4u_p); with u_p(i+1)= max(u_p(i)+h/6*(k1u_p+ 2*k2u_p...

environ 5 ans il y a | 0

Réponse apportée
how can i solve this problem and plotting?
I assume you want to find the values of a that make the integral = 75, for all values of x. if so, then the following should do...

environ 5 ans il y a | 1

| A accepté

Réponse apportée
speeding up my for loop
Is this any quicker? function y = divisors1(N) i = 1:floor(N/2); L = lcm(N,i); y = sum(L==N) + 1; e...

environ 5 ans il y a | 0

Réponse apportée
Mark the knee point on a graph
Calculate a vector of values of P = V.*I then choose the maximum. Something like: P = V.*I; indx = find(P==max(P)); Vp = V(in...

environ 5 ans il y a | 0

| A accepté

Réponse apportée
Discretising a size distribution function and area under the curve
You should have log(sigma)^2, not log(sigma^2). Don't forget the "dx" part when integrating the curve. mu = 0.015; % geometri...

environ 5 ans il y a | 1

Réponse apportée
ODE system initial condition results in infinity/NaN error. Initial conditions cannot be changed. How to evade?
Simply write your differential function as: fu_p = @(D_p,u_p) -18*muG*u_p/(rhoP*D_p^2) + g*(rhoP-rhoG)/rhoP; avoiding any expl...

environ 5 ans il y a | 0

| A accepté

Réponse apportée
Single bubble expansion equation
Try starting your bubble radius as 2*sigma/1.4, rather than 0.

environ 5 ans il y a | 0

| A accepté

Réponse apportée
Coupled rate ODEs with ode45
It can all be done in one script as follows. Because of the orders of magntude difference between the various concentrations th...

environ 5 ans il y a | 0

Réponse apportée
How can I call the highest order solution (e.g. x'') of an ode in another ode?
You can rearrange the equations as follows to get a consistent set: (you will need to use explicit multiplication where my eq...

environ 5 ans il y a | 0

| A accepté

Réponse apportée
How can I make a loop that gives values in each iteration?
Why do you need a loop? There is just one zero between 2 and 8. Your values of w are not used in any meaningful way (they woul...

environ 5 ans il y a | 0

Réponse apportée
How to use ODE 45 to generate a SIR model
Like so: alpha=1.99; beta=1; gamma=1/7; S=0.99; I=0.01; R=0.1; %tstart=0; %tend=100; y=[S,I,R]; tspan=0:1:100; [t,sol...

environ 5 ans il y a | 2

Réponse apportée
error in using the function fsolve to find steady state
Using the Optimization toolbox to solve these equations seems like using a sledgehammer to crack a nut! It is clear from the eq...

environ 5 ans il y a | 0

Réponse apportée
I am trying to solve ODE having more than 1 dependent variable. but I am not able to solve it with dsolve function. please help me to find correct function to solve ODE.This is an mechanical engineering equation so it is bit complicated and lengthy
Here's a possible way using ode45. I've used arbitrary initial values for the three temperatures, so you will need to replace t...

environ 5 ans il y a | 1

| A accepté

Réponse apportée
MATLAB Newton Raphson Method with a function with array/matrix variables
You could do it like this f = @(x,g) g.*exp(x) - 1; df = @(x,g) g.*exp(x); g = [1 2 3 4 5]; for i= 1:numel(g) x0 = 0...

environ 5 ans il y a | 1

| A accepté

Réponse apportée
When i try to create function error "Unable to perform assignment because the left and right sides have a different number of elements." comes up
Try n=-25:25; x3=zeros(1,length(n)); x3(n>=2 & n<=22)=exp(j*(0.5)).^(2:22);

environ 5 ans il y a | 0

| A accepté

Réponse apportée
Explicit Eulers Method for time advancement
T(i)^(n+1) This will raise T(i) to the (n+1)th power! You need another loop for time (say j = 1:something), then you can refer...

environ 5 ans il y a | 0

Réponse apportée
Hot to fit two curves under interdependent constraint ?
How about just using fminsearch x = linspace(1,100,100); % Measurement results: y1=[0.07469056,0.07378624,0.07288704,0.071992...

environ 5 ans il y a | 0

| A accepté

Réponse apportée
Need assistance using bisection method to find equation roots in Matlab function.
Try this % input for function that we're finding the roots of f1 = @(x) ((-0.6)*x^2)+(2.4*x)+(5.5); xl = 5; % xl sets the i...

environ 5 ans il y a | 1

| A accepté

Réponse apportée
Errors in Newton Raphson Code
Again, more like this % f = 3*exp(x)-4*cos(x) % df/dx = 3*exp(x)+4*sin(x) i=1; x=0.1; err = 1; while err>10^-8 && i<100 ...

environ 5 ans il y a | 0

Réponse apportée
Error in Newton-Raphson Method
Like this R=15/2; v=500; h=8; i=1; err = 1; while err>10^-8 && i<100 hold = h; fh = pi*h^2*(3*R - h)/3 - v; ...

environ 5 ans il y a | 0

Réponse apportée
Plotting partial sums of series
Do you mean something like this? x = -pi:0.1:pi ; %initializing x S = zeros(20,numel(x)); figure xlim([1 20]) grid hold o...

environ 5 ans il y a | 0

| A accepté

Réponse apportée
Anonymous function surface plot
Are you looking for something like this? n = 2; x_opt = randi([-6,6],n,1); A = randi(n,n); T = A*A' + eye(n,n); h = -T*x_op...

environ 5 ans il y a | 1

| A accepté

Réponse apportée
Boucle for add the element behind
doc cumsum

environ 5 ans il y a | 1

| A accepté

Réponse apportée
Solving system of ODEs and Plotting
Something like this? timerange= [0 60]; [t, hvl] = ode45(@f, timerange, [0.9,0.1,0.2]); plot(t, hvl, 'LineWidth', 2),grid ...

environ 5 ans il y a | 0

| A accepté

Réponse apportée
Plot 3D of a function
Are you looking for something like this? x = linspace(0,pi); t = linspace(0,1); z = @(x,t) 10*exp(-4*t).*sin(2*x); [x1, t1] ...

environ 5 ans il y a | 0

| A accepté

Réponse apportée
Error using _*_. What am I doing wrong?
You need dots before the * and before the / , not after the t.

environ 5 ans il y a | 1

Réponse apportée
Runge Kutta 4th Order Example
First, write your equation as two first order equations; xdot = v, say, and vdot = -9xdot - 0.1x^3 Then define two functions ...

environ 5 ans il y a | 1

Réponse apportée
Find intersection point between a vertical line and another line.
You could insert a conditional: AlineX=[0 0]; AlineY=[0 400]; BLineX=[1180 570]; BLineY=[-289.5 250]; p1 = polyfit(Alin...

environ 5 ans il y a | 1

| A accepté

Réponse apportée
Solving second order inhomogeneous differential equations which are not a function of time
Break the ode into two first order ode's. e.g. dy/dx = v; dv/dx = f(x) - p*v - q*y; Look up the documentation on ode45 ...

environ 5 ans il y a | 0

| A accepté

Charger plus