Question Number 47036 by 23kpratik last updated on 04/Nov/18
$${let}\:{m},{n}\:{denotes}\:{any}\:{two}\:{possitive},{relative}\:{prime}\:{integers},\:{then}\:{prove}\:{that}\:\phi\left({mn}\right)=\phi\left({m}\right)\centerdot\phi\left({n}\right) \\ $$