Let $H_1,H_2$ be finite field extensions over $\Bbb{Q}$. Suppose $H_1\cap H_2=\Bbb{Q}$, Do we have: $$ [H_1H_2:\Bbb{Q}]=[H_1:\Bbb{Q}]\cdot [H_2:\Bbb{Q}]$$
I know it is true for Galois extension. But it is true for finite extensions?
THANKS!
Let $H_1,H_2$ be finite field extensions over $\Bbb{Q}$. Suppose $H_1\cap H_2=\Bbb{Q}$, Do we have: $$ [H_1H_2:\Bbb{Q}]=[H_1:\Bbb{Q}]\cdot [H_2:\Bbb{Q}]$$
I know it is true for Galois extension. But it is true for finite extensions?
THANKS!