Two rings $R_1$= $\frac{\mathbb{Q}[X]}{X^2}$ and $R_2$= $\frac{\mathbb{Q}[X]}{X^2-1}$ are given I have to show whether they are isomorphic or not
Clearly both are not integral domain but I have not find any explicit isomorphism between them. Neither any criteria to show they are not isomorphic.
Any idea how to show?
