並前往https://math.ymhs.tyc.edu.tw/masterchen/chenyan/TeaPlan108/Contns/1091/%E9%AB%98%E4%BA%8C%E4%B8%8AH/ch2/2.2%20%E5%B0%8D%E6%95%B8%E8%88%87%E5%B0%8D%E6%95%B8%E5%BE%8B(%E4%B8%8A%E8%AA%B2).pdf