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已知等差数列{an}为递增数列,且a2,a5是方程x2-12x+27=0的两根,数列{bn...
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已知等差数列{a
n}为递增数列,且a
2,a
5是方程x
2-12x+27=0的两根,数列{b
n}的前n项和
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEwAAAAjCAYAAAA+NeykAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
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iKh9IKsxncRsJtuB9usPD5WTD0RAQdZi7AQYWATfAjZbp5V2dgYpAObfATYZp5TyjwAD8j85I8AA
Xk6AIbS8rQATYCAB0FwqTICBBEDz8wqbDMkO/5gJXPdnHnUYbRQXq/3t2ADyrEd4Lr/9xXDk8my1
6wknACPRl1YpnKascDcIwpH37ED+i/CcndXGn6XtnwXYbO26CGVAaevS7WLy/xt40yg8Hzy0qRi4
2T9gWlyNKAPK6ZGXsdPkjgUW2jEbP1lhcGtuC6xnhnB3bAC2Duuu+RqKQanUkuE7WnBbYDRHGqgn
Btz5RXb1T1uFne277lNpR2Q+rzHmji+ZRJHfUllpkTZgHBf2pyNVGP5mI0t16O1HeQ27C1ZOx1wZ
cIhHmxVYeToCa9xoOqjCynZcJEybvPDAStGKl+ktxJjC83CvVcf5sVKZw5uDo6ONvvHGdVNBsQA6
oJwVwCeAzV5b5eJ65HhhAkttG/s+lv9zAvdiCDQNdF6MTGDkoF+QZkNypsmpW6bd5SIt+ioseh0j
H5gHpP290sTZQE69ssJ67ouMGNnAwimTXyseOk1P66vvbQQnRiawQh9RFjuuUJc91WgwmZ4k8mLk
ASsA0Sn0tnbcXX18e0HKghkjC1gJKInAt0Crv83AlDw3Rhawxg755M8EGJhWASbAQAKg+R8N/Iun
sO/hhgAAAABJRU5ErkJggg==
)
.
(1)分别写出数列{a
n}和{b
n}的通项公式;
(2)记c
n=a
n+1b
n+1,求证:数列{c
n}为递减数列.
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