等比数列求和公式是什么?
等比数列求和公式是什么?
数学人气:427 ℃时间:2019-09-17 07:40:23
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) 等比数列:a (n+1)/an=q (n∈N).(2) 通项公式:an=a1×q^(n-1); 推广式:an=am×q^(n-m); (3) 求和公式:Sn=n×a1 (q=1) Sn=a1(1-q^n)/(1-q) =(a1-an×q)/(1-q) (q≠1) (q为比值,n为项数) (4)性质:①若 m、n、...
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