function y=sumOfInverses(a,b,c,d)
%SUMOFINVERSES   returns the sum of the 
%  inverses of its scalar arguments.

  if nargin==1 
         y=1/a;
  elseif nargin==2
     y=1/a+1/b;
  elseif nargin==3
     y=1/a+1/b+1/c;
  else
     y=1/a+1/b+1/c+1/d;
  end
end
