Roots of One
Definition
The equation
\[
x^p = 1
\]
has $p$ roots and these are called the $p$
roots of 1.
We call the complex numbers which solve this
equation the $p$th roots of
one or the ($p$th) roots
of unity.
A $n$th root of unity $r \in \R $ is
primitive if it is not
an $m$th root of unity for any $m < n$.