並前往https://math.ymhs.tyc.edu.tw/chenyan/TeaPlan108/Contns/1081/%E9%AB%98%E4%B8%80%E4%B8%8A/Ch1/Ch1.2%E6%8C%87%E6%95%B8%E8%88%87%E5%B8%B8%E7%94%A8%E5%B0%8D%E6%95%B8(%E4%B8%8A%E8%AA%B2).pdf
