acos2d(alpha, beta)

function signedcos = acos2d(alpha, beta)
%ACOS2D      4-quadrant arccosine function, in degrees. 
%
%   ACOS2D(alpha, beta) computes the four-quadrant arccosine of the amgle 
%   [alpha]. For arguments |alpha| > 1, the result is NaN. The resulting 
%   angle is not uniquely determined by alpha, nor by the lengths or 
%   order of the sides of the triangle (as in ATAN2), so an additional 
%   argument [beta] is required. If [beta] < 180, the small angle 
%   (0 <= alpha <= 180) is returned. If [beta] > 180, the large angle
%   (180 < alpha < 360) is returned. 
%
%   See also acos2.

% Rody P.S. Oldenhuis
% Delft University of Technology
% Last edited: 23/Feb/2009

    % compute 4-quadrant cosine by calling ACOS2 directly
    signedcos = acos2(alpha, beta)*180/pi;

end