Math Help - primitive root modulo p

1. primitive root modulo p

Let p,q be odd primes with $p = 2q + 1$

Show that 2 is a primitive root modulo p if and only if $q \equiv 1 (mod 4)$

2. Re: primitive root modulo p

I guess this proves a part of it, sophie germain prime primitive root.

Salahuddin
Maths online