the following rule:

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the following rule:

by sanju09 » Thu Apr 09, 2009 4:20 am
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



OA A
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by moutar » Thu Apr 09, 2009 6:36 am
A prime number has no factors other than 1 and itself. Therefore every number less than p does not have any factor in common other than 1. There are p-1 numbers less than p so answer is A.