版上有許多詢問97年的題目，就是沒問到這題
是太簡單了嗎QQ
A number a is called a fixed pointed of a function f if f(a)=a.
Prove that if f'(x)≠1 for all real numbers x,
then f has at most one fixed point.
不常作這種證明題，懇請各位大哥大姊提點一下