並前往https://math.ymhs.tyc.edu.tw/masterchen/chenjt99/ScrClass/1111/%E9%AB%98%E4%B8%89%E7%B7%B4%E7%BF%92%E5%8D%B7/6%E6%95%B8%E6%93%9A%E5%88%86%E6%9E%90.pdf
