Great Circle Math Formulas

Inverse Cosine    ARCCOS(Y) = -ATAN(Y/SQR(1-Y*Y)) + pi/2

Atan x=x-x^3/3+x^5/5-x^7/7-x^9/9...

Cos (y) = 1- (y)^2/2! + (y)^4/4! - (y)^6/6! + (y)^8/8! -...   				
Sin (y) = (y) - (y)^3/3! + (y)^5/5! - (y)^7/7! + (y)^9/9! -...   					

Radians (y) = (y)/180*pi
