Problem: Show that for each k, the function σk(n)=[SIZE="4"]Ʃ[SIZE="1"]d|n dk is multiplicative.
The attempt at a solution:
What I know is that I am supposed to use the Lemma which states that if g is a multiplicative function and f(n)=Ʃ[SIZE="1"]d|n g(d) for all n, then f is...