help please
1. Let u_{1} be the identity function, u_{1}(n)=n. Prove that summation of u1(d)=sigma(n)
and
2. If f and g are muktiplicative, prove that the pointwise product, fg, is also multiplicative.
[fg(n)=f(n)g(n)]
thanks in advance
help please
1. Let u_{1} be the identity function, u_{1}(n)=n. Prove that summation of u1(d)=sigma(n)
and
2. If f and g are muktiplicative, prove that the pointwise product, fg, is also multiplicative.
[fg(n)=f(n)g(n)]
thanks in advance