因为9 又1 10.导学号26394000在等比数列{an}中,若a1>0,q>0,前n项和为Sn,试比较S_3/a_3 与 S_5/a_5 的大小. 解当q=1时,S_3/a_3 =3,S_5/a_5 =5,所以S_3/a_3 当q>0,且q≠1时, S_3/a_3 -S_5/a_5 =(a_1 "(" 1"-" q^3 ")" )/(a_1 q^2 "(" 1"-" q")" )-(a_1 "(" 1"-" q^5 ")" )/(a_1 q^4 "(" 1"-" q")" ) =(q^2 "(" 1"-" q^3 ")-(" 1"-" q^5 ")" )/(q^4 "(" 1"-" q")" )=(q^2 "-" 1)/(q^4 "(" 1"-" q")" )=("-" q"-" 1)/q^4 <0, 所以有S_3/a_3 B组 1.(2017河北衡水模拟)已知01,则( ) A.logac