a=input("a = ")
u(1)=a;v(1)=-3*a/4;w(1)=3*u(1)+4*v(1)
for k=1:40
    u(k+1)=(u(k)+4*v(k))/5
    v(k+1)=(3*u(k)+2*v(k))/5
    w(k+1)=3*u(k+1)+4*v(k+1)
end
afficher ([u,v,w])
 