12345678910111213141.(2024·山东日照二模)已知数列{an}各项均为正数,首项a1=3,且数列{log3an}是以-2为公差的等差数列,则a3=(　　)A 解析 因为数列{an}各项均为正数,首项a1=3,则log3a1=1.又数列{log3an}是以-2为公差的等差数列,则log3a3=1-2×(3-1)=-3,故a3=3-3 .故选A.12345678910111213142.(2024·广东广州三模)等比数列{an}满足a1+a3=10,...