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Question

Math 6310 • Algebra

Spring 2004 • Question 10

Let \(E\) be an extension of the field \(F\) and let \(\alpha \) be an element of \(E\) which is algebraic over \(F\) of degree \(n\).

  1. If \(n\) is prime to 2, prove that \(F(\alpha ^2)=F(\alpha )\).
  2. Give an example in which \(n\) is prime to 3 but \(F(\alpha ^3)\ne F(\alpha )\).

Raw LaTeX

Let \(E\) be an extension of the field \(F\) and let \(\alpha\) be an element of \(E\) which is algebraic
over \(F\) of degree \(n\).
\begin{enumerate}
\item[(a)] If \(n\) is prime to 2, prove that \(F(\alpha^2)=F(\alpha)\).
\item[(b)] Give an example in which \(n\) is prime to 3 but \(F(\alpha^3)\ne F(\alpha)\).
\end{enumerate}