function s = geometric_series(a, r)
%   GEOM_SERIES a, r
%   GEOM_SERIES(A, R) computes the geometric series
%   A + AR + AR^2 + AR^3 + AR^4 + ...
%   as
%     A
%   -----
%   1 - R

error(nargchk(2, 2, nargin));

s = a / (1 - r);