The Euler phi-function is defined for positive integers n by φ (n) = s, where 5 is the num...

The Euler phi-function is defined for positive integers n by φ (n) = s, where 5 is the number of positive integers less than or equal to n that are relatively prime to n Use Exercise 45 to show that

the sum being taken over all positive integers d dividing 11. [Hint: Note that the number of generators of ℤd is φ (d) by Corollary 6.16.]