The ring $F[x]/\langle x^2\rangle$ for an infinite field $F$ is an infinite commutative ring with identity which isn't a domain.
I'm still stuck in understanding why is it not a integral domain.i.e. which element it contains are non-zero zero divisors..Please help ...
Hint: For $p\in F[x]$ denote $\bar{p}=p+\langle x^{2}\rangle$. What is $\bar{x}\cdot\bar{x}\,?$