An arithmetico-geometric sequence has terms of the form [ t_n = [a+(n-1)d], r^{n-1} ] Sums are found by the standard method: write (S), form (rS), subtract, and sum the resulting G.P.
An arithmetico-geometric sequence has terms of the form [ t_n = [a+(n-1)d], r^{n-1} ] Sums are found by the standard method: write (S), form (rS), subtract, and sum the resulting G.P.