【简答题】已知实数列{a n }是等比数列,其中a 7 =1,且a 4 ,a 5 +1,a 6 成等差数列. (1)求数列{a n }的通项公式; (2)数列{a n }的前n项和记为S n ,证明:S n <128(n=1,2,3…).
【判断题】Paper cutting is originated in the Han Dynasty.
【判断题】The clothing in the Han Dynasty were more conservative. ( )
【判断题】6 The Lantern Festival originated in the Han Dynasty in honor of Buddhists.
【简答题】已知实数列{a n }是等比数列,其中a 7 =1,且a 4 ,a 5 +1,a 6 成等差数列。 (1)求数列{a n }的通项公式; (2)数列{a n }的前n项和记为S n ,证明:S n <128(n=1,2,3,…)。
【单选题】Who started the Silk trade road in the Han Dynasty?