Quadratic Residue/Examples/3

Example of Quadratic Residues
There exists exactly $1$ quadratic residue modulo $3$, and that is $1$.

Proof
To list the quadratic residues of $3$ it is enough to work out the squares $1^2$ and $2^2$ modulo $3$.

So the set of quadratic residues modulo $3$ is:
 * $\set 1$

The set of quadratic non-residues of $3$ therefore consists of all the other non-zero least positive residues:
 * $\set 2$