【简答题】设数列{a n }的前n项积为T n ,已知对?n,m∈N + ,当n>m时,总有 T n T m = T n-m ? q (n-m)m (q>0是常数). (1)求证:数列{a n }是等比数列; (2)设k,m,n(k<m<n)成等差数列,试比较T n ?T k 和(T m ) 2 的大小,并说明理由; (3)探究:命题p:“对?n,m∈N + ,当n>m时,总有 T n T m = T...
【单选题】Here is a survey about how the 1,000 students from No. 2 Middle School go to school on weekdays. One third of the students going to school by bike are girls. Then according to the form below, ______ ...
【简答题】设等比数列{a n }的前n项和为S n ,已知a n + 1 = 2S n + 2 (n∈N * ). (1)求数列{a n }的通项公式; (2)在a n 与a n + 1 之间插入n个数,使这n + 2个数组成一个公差为d n 的等差数列. ①在数列{d n }中是否存在三项d m ,d k ,d p (其中m,k,p成等差数列)成等比数列?若存在,求出这样的三项,若不存在,说明理由; ②求...