已知数列{an}满足a1=1,an+an+1=(14)n(n∈N+),Sn=a1 发布时间:2017-05-18 11:50 │ 来源:www.tikuol.com 题型:选择题 问题: 已知数列{an}满足a1=1,an+an+1=(14)n(n∈N+),Sn=a1+4a2+42a3+…+4n-1an,类比课本中推导等比数列前n项和公式的方法,可求得5Sn-4nan=( )A.n2B.nC.n+1D.n-1
题型:选择题 Mr Li taught me _____ in the river when I was a child. [ ]A. to swim B. swam C. swimmingD. swims 查看答案