>> m=10;
>> b=0.1;
>> k=1000;
>> wn=sqrt(k/m)

wn =

    10

>> num=[4];
>> den=[1 0.5 0];
>> v=[-5 5 -5 5];
>> axis(v);

syms Y s y(t) t
 
laplace(10*diff(diff(y(t)))+0.4*diff(y(t))+4*y(t))
Y1=s*Y;
Y2=s*Y1;
sol=solve(10*Y2+0.4*Y1+4*Y-1,Y);
pretty(sol)
 
num=[1];
den=[10 0.4 4];
h=tf(num, den);
[A,B,C,D]=tf2ss(num, den)

syms x y;
u=dsolve('D2y+0.04*Dy+0.4*y=0','x')
U=dsolve('D2y+0.04*Dy+0.4*y=0','y(0)=1','Dy(0)=1','x');
subs_U=subs(U,x,0:0.1:250);
t=0:0.1:250;
plot_U=double(subs_U);
plot(t,plot_U)
hold on

figure
num=[1];
den=[10 0.4 4];
h=tf(num, den);
step(h)

>> controlSystemDesigner(tf(1,[1,2]))