判断数列是收敛，还是发散？对于收敛数列，通过观察数列[tex=2.0x1.357]h3eICLkAlY54v5UBwjQ4sBI1zHM9ZDqJprUj0GNfH3U=[/tex]的变化趋势，写出它们的极限[tex=4.071x2.429]mBCZQMW/5LjRNwAQZYRVR5iAKFzpZ1HscYN6r8dR5rE=[/tex]