已知数列{An}中,A1=1,n大于或等于2,n为正整数时前n项和Sn满足Sn^2=An(Sn-1/2)
2个回答
1.
S1=A1=1
Sn^2=(Sn-Sn-1)(Sn-1/2)化简为:
2SnSn-1=-Sn-Sn-1
等号两边都除以SnSn-1得出:
1/Sn-1/Sn-1=2
所以{1/Sn}是等差数列
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