function s=expseries(x,n);
% EXPSERIES: function calculates the sum
% 1+x+(x^2)/2!+(x^3)/3!+...+(x^n)/n! (up to nth power).
% Call syntax:
%         s=expseries(x,n);
% where x is real and n nonnegative integer.
k = 0:n;                         % create a vector from 0 to n
series = (x.^k)./factorial(k);   % create a vector of terms in the series
s = sum(series);                 % sum all terms of the vector 'series'.