I tried to reproduce the results of the 6-row table showing "n, CDiff and ADiff" (above) by using EXCEL, and I did succeed, but only after I made three corrections to the logic of the program: 1) change "South" to Zero, since theta should simply be "angle/2", not "south + (angle/2)", 2) for the Inscribed calculations, change "b=cos(theta)" to "b=sin(theta)" -- Ooops! since cos is the length of the adjacent side, not the length of the opposite side, and 3) for the Inscribed calculations, change "h=sin(theta)" to "h=cos(theta)" -- Ooops! since sin is the length of the opposite side, not the length of the adjacent side. Note also that the formulas for "h" and "b" under the "inscribed" diagram at the top also appeared to be switched in error. Anyway, after I made these three changes, I was able to reproduce the CDiff and ADiff for n=40 through n=100 exactly (to the fifth decimal place), so I'm pretty confident my changes were necessary. (Also, the changes made perfect sense to me... since I was always taught that a cosine is the "length of the adjacent side of the triangle", etc.)