I like ____________.[ ] A. making kites 发布时间:2017-04-10 00:42 │ 来源:www.tikuol.com 题型:选择题 问题: I like ____________.[ ]A. making kitesB. makeing kitesC. making kite
题型:选择题 已知数列{an}满足:a1=14,a2=34,an+1=2an-an-1(n≥2,n∈N*),数列{bn}满足b1<0,3bn-bn-1=n(n≥2,n∈N*),数列{bn}的前n项和为Sn.(Ⅰ)求证:数{bn-an}为等比数列;(Ⅱ)求证:数列{bn}是单调递增数列;(Ⅲ)若当且仅当n=3时,Sn取得最小值,求b1的取值范围. 查看答案