real   y1, y2, x1, x2
      real*8 yy1, yy2, xx1, xx2
c
      write(6,'(5x,a,5x,a,3x,a,3x,a,8x,a)')
     $    'I','SQRT(I)','SQRT(I+1)-SQRT(I)','EXACT(7)','REL. ERR.'
      do i = 0 , 100000, 1000
         x1 = sqrt(real(i))
         x2 = sqrt(real(i+1))
         y1 = x2 - x1
         y2 = 1 / ( x1 + x2 )
         write(6,'(i6,3f15.10,e20.10)') i, x1, y1, y2, (y2-y1)/y2
      end do
c
      write(6,*)
      write(6,'(5x,a,5x,a,3x,a,3x,a,7x,a)')
     $    'I','SQRT(I)','SQRT(I+1)-SQRT(I)','EXACT(15)','REL. ERR.'
c
      do i = 0 , 100000, 1000
         xx1 = sqrt(dble(i))
         xx2 = sqrt(dble(i+1))
         yy1 = xx2 - xx1
         yy2 = 1 / ( xx1 + xx2 )
         write(6,'(i6,3f15.10,e20.10)') i, xx1, yy1, yy2, (yy2-yy1)/yy2
      end do
      end