On Sun, 5 Dec 1999 09:24:25 +0200 Quentin writes: >This might seem waaay OT but there is a PIC in there somewhere. >Can somebody please help this rusted brain: > >I've been given information as such: >if x=0, y=0 >x=15, y=0.259 >30, 0.5 >45, 0.707 >60, 0.866 >75, 0.966 >90, 1.000 > >You will see that while X is linear, Y is not (Log??). With these >information available, how would I calculate Y for all the other >values >of X? > >I want to use it in a lookup table in the PIC. Well, I HAVE done a 7th order power series by solving 7 equations with 7 unknowns (the coefficients). It worked, but was a lot of trouble. Last time, I used a standard curve fitting program (Curve Expert). Jack Crenshaw mentions a bunch of them in the December issue of Embedded Systems Programming. Here are the ones he lists: http://www.micromath.com/scientist.html http://www.spss.com http://www.ebicom.net/~dhyams/cvxpt.htm Harold ___________________________________________________________________ Why pay more to get Web access? Try Juno for FREE -- then it's just $9.95/month if you act NOW! Get your free software today: http://dl.www.juno.com/dynoget/tagj.