The sum of the first n terms of geometric series is: when q≠ 1, Sn = a1(1-q n)/(1-q) = (a1-anq)/(/kloc). When q= 1, Sn=na 1 (where a 1 is the first term, an is the nth term, d is the tolerance, and q is the equal proportion). In addition, Sn is the sum of the first n terms.

nature

(1) if m, n, p, q∈N+, m+n=p+q, then am×an=ap×aq.

(2) In a geometric series, every k term is added in turn, which is still a geometric series.

(3) "G2 = AB (G ≠ 0)" If "G is the proportional average of A and B".