A necessary and sufficient condition is established for 1, \cos (\pi r_1), and \cos (\pi r_2) to be rationally independent, where r_1, r_2 are rational numbers. The elementary computational argument yields linear independence over larger number fields as well.

Additional Information

Author(s)

Berger, Arno

DOI

https://doi.org/10.37193/CJM.2018.02.04