atan  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: atan (/thread34559.html) 
atan  hugh steers  05222003 i see luiz has an article on trigs for the 16c (possibly also the 17bii). sorry, i missed this thread.
however, on the subject of inverses, i spent a while some time ago developing a fast arctan (but only single precision accuracy) using a limited pade approximation. (sorry about the bad formatting, it gets mangled) #define M_PI 3.141592654f #define A0X 0.2388229612f #define A1X 2.445205396f #define B1X 3.943529789f #define A2X 1.314747223f #define B2X 1.798249626f
float atan6(float x)
