並前往https://math.ymhs.tyc.edu.tw/chenjt99/ScrClass/1041/%E7%BF%92%E4%BD%9C/%E9%AB%98%E4%BA%8C%E4%B8%8A/CH1.3%E6%AD%A3%E5%BC%A6%E5%AE%9A%E7%90%86%E8%88%87%E9%A4%98%E5%BC%A6%E5%AE%9A%E7%90%86.pdf