ODE45 solver solution : subprogram

%
%   Mass-Spring-Damper system 
%   ODE45 solver solution
%   ODE45 subprogram
%

function ydot = forcedsub(t,y)

m = 2;			%  mass of the system in meter
k = 5000;		%  stiffness of the spring (N/m)
c = 30;			%  damping coefficient
P = 100;		%  magnitude of force
Omega = 20;		%  frequency of force
	
yd1 = y(2);
yd2 = (-k*y(1)-c*y(2)+P*sin(Omega*t))/m;

ydot = [yd1;yd2];