Talk:Cosine of Integer Multiple of Argument/Formulation 3

Presumably (as there's no citation for this) you pulled this out of the top of your head?

Being that this may be the case, would it not be an improvement to invoke Difference of Squares of Secant and Tangent and simplify the result?

There's a reason for preferring to post up "published" results rather than arbitrary identities that are thought up, and that is that if it's been published, then it's been at least peer-reviewed, and thus it has a higher probability of being optimised and (in extreme cases) corrected (and, indeed, checked for intrinsic "usefulness" as well). --prime mover (talk) 05:56, 26 June 2020 (UTC)