来自罗立的问题
设等比数列{an}满足:a1=13,a2+a3=427,且an>0.(Ⅰ)求数列{an}的通项;(Ⅱ)设bn=nan,求数列{bn}的前n项和Sn.
设等比数列{an}满足:a1=13,a2+a3=427,且an>0.
(Ⅰ)求数列{an}的通项;
(Ⅱ)设bn=nan,求数列{bn}的前n项和Sn.
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2020-12-1921:32
设等比数列{an}满足:a1=13,a2+a3=427,且an>0.(Ⅰ)求数列{an}的通项;(Ⅱ)设bn=nan,求数列{bn}的前n项和Sn.
设等比数列{an}满足:a1=13,a2+a3=427,且an>0.
(Ⅰ)求数列{an}的通项;
(Ⅱ)设bn=nan,求数列{bn}的前n项和Sn.
(Ⅰ)∵等比数列{an}满足:a1=13