数列{an}满足an=2an-1+2n+1(n∈N,n≥2),a3=27.(Ⅰ) 发布时间:2017-05-03 20:33 │ 来源:www.tikuol.com 题型:解答题 问题: 数列{an}满足 an=2an-1+2n+1(n∈N,n≥2),a3=27.(Ⅰ)求a1,a2的值;(Ⅱ)记bn=12n(an+t)(n∈N*),是否存在一个实数t,使数列{bn}为等差数列?若存在,求出实数t;若不存在,请说明理由;(Ⅲ)求数列{an}的前n项和Sn.
题型:解答题 —Is it far from your home to school? —Not very, only _________. [ ]A. 15 minute's ride B. 15 minutes' ride C. 15 minutes ride D. 15 minutes' rides 查看答案