Fast and Accurate Trigonometric Functions on the HP17BII  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: Fast and Accurate Trigonometric Functions on the HP17BII (/thread105900.html) 
Fast and Accurate Trigonometric Functions on the HP17BII  Gerson W. Barbosa  01122007 To all who might be interested, just available at the Articles Forum: Fast and Accurate Trigonometric Functions on the HP17BII Accurate? Surely! Fast? Well, kind of. But I wanted to make up a trilogy :) Fast and Accurate Trigonometric Functions on the HP12C Platinum Fast and Accurate Trigonometric Functions on the HP12C Thanks Charles for first noticing the simpler equations were better. Regards,
Re: Fast and Accurate Trigonometric Functions on the HP17BII  Karl Schneider  01142007 Hi, Gerson  Thank you for posting your dedicated work in the Articles Forum. They are certainly worthy, and probably more appropriate there than in the Software Library, due to the appliedmathematics content. I expect that the HP17BII programs will work on the HP17B, as well? Regards,
 KS
Re: Fast and Accurate Trigonometric Functions on the HP17BII  Gerson W. Barbosa  01142007 Hello Karl, I don't have an HP17B but I think the equations should run just fine on it. I'd like to test the equations on the HP17BII+ also. The HP200LX was a good developing tool, but when solving for the inverse functions using the fullrange equations I noticed the HP17BII behaved differently. That's why I had to append the apparently useless terms to the cosine and tangent equations in the what I called IFLESS EQUATIONS sets (that was an experiment I decided to keep). I have just included a note at the end about a even shorter minimax polynomial equation (see my reply to Charles, which ended up orphan). The minimax polynomial is accurate in the range 18 to 18 degrees, that is, +/ 90/5. It is then expanded to 90 to 90 degrees by means of
This doesn't improve the solving time but makes the equation shorter. Reducing the range even more would actually make the equation slower and longer. I think this is the right balance between size and speed. Regards,
Gerson. Edited: 14 Jan 2007, 2:38 a.m.
