Minimal polynomials of algebraic cosine values at rational multiples of $\pi $
J. Integer Seq. 19(2), Article 16.2.8, 8 p., electronic only (2016)
Summary
Summary: Lehmer proved that the values of the cosine function evaluated at rational multiples of $\pi $ are algebraic numbers. We show how to determine explicit, closed form expressions for the minimal polynomials of these algebraic numbers.
