program second
      implicit none

      real xe(2),t,dt,x2(2),fe1,fe2,f21,f22

      xe(1) = 0
      xe(2) = 0
      x2(1) = 0
      x2(2) = 0
      dt = 0.1

      open(13,file='data.d')

      do 20 t=0,20,dt
         write(13,15) t,xe(1),xe(2),x2(1),x2(2),0.5*t*sin(t)
         fe1 = xe(2)
         fe2 = -xe(1)+cos(t)
         f21 = x2(2)
         f22 = -x2(1)+cos(t)
         xe(1) = xe(1) + fe1*dt
         xe(2) = xe(2) + fe2*dt
         x2(1) = x2(1)+f21*dt+0.5*(-x2(1)+cos(t))*dt**2
         x2(2) = x2(2)+f22*dt+0.5*(-x2(2)-sin(t))*dt**2
 20   continue
      write(13,15) t,xe(1),xe(2),x2(1),x2(2),0.5*t*sin(t)
      close(13)

 15   format(6(F8.2))
      end