Check this out! You can feed that equation (or just about any other) into
the following site and get source code that evaluates it back.
http://www.markworld.com/microtools.html  Excellent math (Generate 8 or 16
bit PIC code to evaluate an infix expression.     Analyze an IEEE floating
point number) also servos.

For sin Scott Dattalo has it dead at:
http://www.dattalo.com/technical/software/pic/picsine.html
as does Eric Smith
http://www.brouhaha.com/~eric/pic/sine.html

All of this was on the pic FAQ at
http://www.piclist.com

or directly at:
http://204.210.50.240/techref/default.asp?url=microchip/routines.htm#math

---
James Newton mailto:jamesnewton@geocities.com 1-619-652-0593
http://techref.homepage.com The Technical Details Site.
Members can add private/public comments/pages ($0 TANSTAAFL web hosting)


-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Phu T. Van
Sent: Monday, January 31, 2000 18:13
To: PICLIST@MITVMA.MIT.EDU
Subject: Math


Hi. I've got a problem I don't quite know how to tackle.
I need to program the following function for a 16F84 :

P(n) = x - (x^3/6) + (x^5/120) - (x^7/5040)

I don't know what this approximation is called or if it really works the
way it's supposed to. I got it from a local math whiz; supposedly it
will approximate sine of x where x is the angle in radians.

Anyhow, I need a reliable, fast and efficient way to calculate sine in
realtime to do navigation. I've heard about lookup tables but apparently
that is said to consume a huge amount of memory and processing power.
I'd like to stick with the PIC if possible.

Any/all inputs appreciated.

--Phu T. Van