can somoene pls prrovide a complete proof that if (m1,m2) =1 then phi(m) is multiplicative?
and can someone pls provide me a method for computing phi(2004)
Thanks in advance
1. Given that by Möbius inversion formula we have that and since is multiplicative it follows that is multiplicative (if is multiplicative then so is )
Note also that (where the product runs through the prime divisors of n)
2. Consider the Inclusion-exclusion principle - Wikipedia, the free encyclopedia
and calculate , and from there find the formula for and conclude that it's multiplicative
To calculate find the prime divisors of 2004, these are and thus: