Let \(E\) be an extension of the field \(F\) and let \(\alpha \) be an element of \(E\) which is algebraic over \(F\) of degree \(n\).
- If \(n\) is prime to 2, prove that \(F(\alpha ^2)=F(\alpha )\).
- Give an example in which \(n\) is prime to 3 but \(F(\alpha ^3)\ne F(\alpha )\).