trigonometry – Demonstration code for cos and sin in TeX macros

A doc­u­ment that both pro­vides macros that are us­able else­where, and demon­strates the macros.
The code uses the “clas­si­cal” an­a­lyt­i­cal ex­pan­sion of sin and cos (the more re­cent trig uses a “nu­mer­i­cal an­a­lyst’s” ex­pan­sion).