        implicit real*8 (a-h,o-z)
        parameter (nb=100000)
        dimension x(0:nb)
       
        open(2,file='parametros')
c        read(2,*) m, b , k
       h=0.01
       N=10**4
       f=0.
       m=1.d0
       b=0.1
       k=1.5
       x(0)=1.
       x(1)=x(0)+f*h
       do i=2,N
       x(i)=2*x(i-1)-x(i-2)-b*(h/m)*(x(i-1)-x(i-2))-(k*h*h/m)*x(i-2)
       write(2,*) i*h,x(i)
       enddo
       end
