数列〔an〕的各项都是正数,其前n项和为Sn满足an+Sn=4.求数列an的通项公式②设bn=〔1/（2-log2an）〕^2,{bn}的前n项和为Tn,证当n≧2时Tn

数列〔an〕的各项都是正数,其前n项和为Sn满足an+Sn=4.求数列an的通项公式②设bn=〔1/（2-log2an）〕^2,{bn}的前n项和为Tn,证当n≧2时Tn
数列〔an〕的各项都是正数,其前n项和为Sn满足an+Sn=4.求数列an的通项公式
②设bn=〔1/（2-log2an）〕^2,{bn}的前n项和为Tn,证当n≧2时Tn

数列〔an〕的各项都是正数,其前n项和为Sn满足an+Sn=4.求数列an的通项公式②设bn=〔1/（2-log2an）〕^2,{bn}的前n项和为Tn,证当n≧2时Tn
n=1,a1=2,
n>1,an-1+Sn-1=4(1)
an-Sn=4 (2) (2)-(1) an/an-1=1/2,an=2x(1/2)^(n-1)=0.5^(n-2) n为正整数
(2)补充问题你在检查一下,该题考点不等式放缩