职教组卷基于海量职教高考试题库建立的在线组卷及学习系统
职教组卷
  • 题型:解答题 题类:模拟题 难易度:较易

    已知数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),满足\(S_{n}=2a_{n}+2n-5\),\((n∈N_{+}).\)
    \((\)Ⅰ\()\)求证:数列\(\{a_{n}-2\}\)为等比数列;
    \((\)Ⅱ\()\)记\(b_{n}= \dfrac {a_{n}-2}{a_{n+1}a_{n}}\),数列\(\{b_{n}\}\)的前\(n\)项和\(T_{n}\),求证:\(T_{n} < \dfrac {1}{3}\).
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