Question Number 122637 by sina1377 last updated on 18/Nov/20
$${can}\:{anybody}\:{do}\:{me}\:{a}\:{faver}\:{and}\:{tell}\:{me}\:{what}\:\:{the}\:\:{direct}\:{proof}\:{of}\:\:{mobius}\:{inversion}\:{formula}\:{is}?\:\left({proof}\:{without}\:{using}\:\:{Dirichlet}\:{convolutions}\right)? \\ $$$$ \\ $$