<div id="comment:0"></div> In the current [development version of pynac](https://github.com/pynac/pynac) the evaluation of trigonometric functions has been improved. This enables the following behavior: ``` sage: var('k', domain='integer') k sage: sin(k*pi) 0 sage: cos(k*pi) (-1)^k sage: sin(1 + 2*k*pi) sin(1) sage: tan(k*pi) 0 sage: cos(2*k*pi + pi/3) 1/2 ``` and so on. Additionally, this introduces simplification for the complex exponential function: ``` sage: exp(2*k*pi*I) sage: 1 ``` This ticket shall document these changes. Depends on #20134 CC: @rwst Component: **symbolics** Keywords: **pynac** Author: **Benjamin Hackl** Branch/Commit: **[`edec004`](https://github.com/sagemath/sagetrac-mirror/commit/edec0041a0ef6df6df2acba2f20caea1b043178f)** Reviewer: **Ralf Stephan, Julian Rüth, Travis Scrimshaw** _Issue created by migration from https://trac.sagemath.org/ticket/20099_