Idempotents in group rings (Ex)

Let $p$$<wikitex>; Let $p$ be a prime. Find all the idempotents in the group rings $R[\Zz/p|$ for $R = \Zz$, $R = \Cc$ and $R = \mathbb{F}_p$. </wikitex> == References == {{#RefList:}} [[Category:Exercises]] [[Category:Exercises with solution]]p$ be a prime. Find all the idempotents in the group rings $R[\Zz/p|$$R[\Zz/p|$ for $R = \Zz$$R = \Zz$, $R = \Cc$$R = \Cc$ and $R = \mathbb{F}_p$$R = \mathbb{F}_p$.