Question

Let f:ℤ+ → ℤ+ be the function defined by: for each x ∈ ℤ+, f(x) is the number of positive divisors of x.

- find integers m, n, and k so tha f(m)=3, f(n) = 4 anf f(k) = 5
-is f one-to one? Explain, is f unto? prove
is it true that all positive odd integers a and b, f(ab) = f(a) f(b)? prove answer