PP PS 2 Q37

[nemolee]

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)
(D)
(E) 2

ANS: A

(這題之前有人討論過，可是電腦怪，沒辦法接著原PO來問問題，請大大見諒，會快快把電腦重灌好.... )