How can i solve this function below ?

To solve a second order differential equation : dx/dt = Ax + Bu(t) I use this function but i haven't obtain any result :
function xdot = msd(t,x)
% Function file for mass with spring and damping.
% Position is first variable, velocity is second variable.
u = 10;
m = 1;c = 2;k = 5;
A = [0, 1;-k/m, -c/m];
B = [0; 1/m];
xdot = A*x+B*u;
[t, x] = ode45(@msd, [0,5], [0,0];

 Accepted Answer

Azzi Abdelmalek
Azzi Abdelmalek on 29 Mar 2016
Edited: Azzi Abdelmalek on 29 Mar 2016
Save the function below as msd.m
function xdot = msd(t,x)
% Function file for mass with spring and damping.
% Position is first variable, velocity is second variable.
u = 10;
m = 1;c = 2;k = 5;
A = [0, 1;-k/m, -c/m];
B = [0; 1/m];
xdot = A*x+B*u;
then in Matlab Windows Command write
[t, x] = ode45(@msd, [0,5], [0,0]);
plot(t,x)

3 Comments

But there is an error in this line : xdot = A*x+B*u;
Use
[t, x] = ode45(@msd, [0,5], [0;0]);
Best wishes
Torsten.
it was very useful Mr. Torsten. Can you please explain
[t, x] = ode45(@msd, [0,5], [0;0]);
I want to understand the reason behind using this code.
Kindly help.

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