Question 151
Show that for positive integers $n$,
$$
\sum_{d \mid n} \frac{\mu(d)}{d} = \frac{\phi(n)}{n}
$$
$$
\sum_{d \mid n} \frac{\mu(d)}{d} = \frac{\phi(n)}{n}
$$
MathNet 2007-part-03 — 185 problems (EN–VI) Question 151
Math Olympiad Vault · MathNet 2007-part-03 — 185 problems (EN–VI)