This lecture is part of an online course on Galois theory.
We review some basic results about field extensions and algebraic numbers.
We define the degree of a field extension and show that a number is algebraic over a field if and only if it is contained in a finite extension. We use this to show that the sum and product of algebraic numbers is algebraic, and that a root of a polynomial with algebraic coefficients is algebraic.
Негізгі бет Galois theory: Field extensions
Пікірлер: 45