C double precision trigonometry functions originally for Tandy Color Computer (CoCo) OS9.

Written by Al Buist, who passed away in 1985. License is Public Domain. In the 90's I used these routines while implementing a floating point emulator. This code is in K&R C, so some changes would need to be made for use with a modern C compiler. Also, if you use this for anything real, I would double check the constants against the magazine listing. I found this code on an FTP site around 15 years ago, but it's disappeared. I have no idea if it came from a digital archive, or if someone typed it in by hand.

Originally published in Rainbow Magazine, April 1986, page 238:

https://archive.org/details/rainbowmagazine-1986-04/page/n239/mode/2up