clear;
        j = 0;
        sum = 1.;
        c =  3.;
        limit = exp(c);
        a = 1.;

        while ( abs(sum-limit) > 1.e-5 )
          j = j+1;
%usual method
%         sum = sum + c^j/factorial(j);
% extra credit
          a = a*c/j   
          sum = sum + a 
        end

        N = j
        err = abs(sum - limit)