program roten

      integer n
      double precision x, dx, tol

      x = 1
      tol = 1e-10
      dx = 2*tol

      n = 0
      do while (abs(dx) > tol)
         n = n + 1
         dx = cos(x) - x
         x = x + dx
         write (*,*) n, x
      enddo

      stop
      end