Question

if n>2 .prove that phy (n) is even.​

Answer 1

Step-by-step explanation:

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If (a,n) =1 then (n-a,n)=1 for a€ Z

=>Integers coprime to n occur in pairs of the form a,n-a

=>∅(n)is even

Therefore ∅ (n) is odd for n=1 and n=2 only.

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Answer 2

Answer:-

An even number N can be written as: N=2k. If n is even you can write n=2r, so: n2=4r2=2(2r2). If you put 2r2=k you get: N=2k