% cosine_half.m
% Apply the half-cosine formula twice.
%
c = cos ( pi / 3 )          % c =the cosine of pi/3 = 180/3 = 60 degrees.

c = sqrt ( ( 1 + c ) / 2 )  % Replace c by cosine of 60/2 = 30 degrees = (pi/6).

c = sqrt ( ( 1 + c ) / 2 )  % Replace c by cosine of 30/2 = 15 degrees = (pi/12).

cos ( pi / 12 )             % Ask MATLAB directly for the result.
