37.5174-!-item-!-187;#058&004144
The function f is defined for all positive integers n by the following rule: f(n) is the number of positive integers each of which is less than n and has no positive factor in common with n other than 1. If p is any prime number then f(p) =
(A) p - 1
(B) p - 2
(C) (p+1)/2
(D) (P-1)/2
(E) 2
Ans:(a)
題目解釋f(n)的定義,簡單的說就是n的因素一定是質因素就對了(因為小於N而且只有1個因素) 可是f(p)...怎麼意思咧
why.......