Find the necessary and sufficient condition on integers $D_1,D_2$ for fields $\mathbb{Q}(\sqrt{D_1})$ to be isomorphic to $\mathbb{Q}(\sqrt{D_2})$
How should I start this problem?
Find the necessary and sufficient condition on integers $D_1,D_2$ for fields $\mathbb{Q}(\sqrt{D_1})$ to be isomorphic to $\mathbb{Q}(\sqrt{D_2})$
How should I start this problem?
Theorem: Let be $k$ is a field and $\alpha,\beta$ algebraic over $k$ ,then the map $f:k(\alpha)\to k(\beta)$ is isomorphism if and only if $a,b$ Conjugate element ((i.e roots to same polynomial)).