1、【等差数列】本卷共100分，考试时间90分钟一、选择题(每小题4分，共40分)1. 数列的一个通项公式是 （ ）A. B. C. D. 2. 已知，则数列是 （ ）A. 递增数列 B. 递减数列 C. 常数列 D. 摆动数列3. 数列的通项公式为，则数列各项中最小项是 （ ）A. 第4项 B. 第5项 C. 第6项 D. 第7项4. 设是公差为正数的等差数列，若=80，则=（A）120（B）105（C）90（D）755. 等差数列中，前项，则的值为A. B. C. D. 66. 已知某等差数列共有10项，其奇数项之和为15，偶数项之和为30，则其公差为（ ）A.3 B.4 C.5 D.27.
2、等差数列中，（ ）A24B22C20D-88. 已知等差数列中，则前10项和=（A）100（B）210（C）380（D）4009. 设是等差数列的前n项和，若S7=35，则a4=（A）8（B）7（C）6（D）510. 已知为等差数列，是等差数列的前项和，则使得达到最大值的是（ ） A.21 B.20 C.19 D.18二、填空题(每小题4分，共16分)11. 数列的前n项和，则 。12. 已知an为等差数列，且a72a41，a30，则公差d 13. 已知椭圆+=1上有n个不同的P1,P2,P3,Pn,设椭圆的右焦点为F，数列|FPn|的公差不小于的等差数列，则n的最大值为 14. 某单位用3.
3、2万元购买了一台实验仪器，假设这台仪器从启用的第一天起连续使用，第天的维修保养费为元,若使用这台仪器的日平均费用最少，则一共使用了 天三、解答题(共44分，写出必要的步骤)15.（本小题满分10分） 已知数列中，数列满足；（1） 求证：数列是等差数列；（2） 求数列中的最大值和最小值，并说明理由16. （本小题满分10分） 在数列中，（1）设证明是等差数列;（2）求数列的前项和。17. （本小题满分12分）已知等差数列的前三项为记前项和为()设，求和的值；()设，求的值18. （本小题满分12分）设数列的前项和为。（I）求证：是等差数列；（）设是数列的前项和，求；（）求使对所有的恒成立的整数的
4、取值集合。答案一、选择题1. B2. A3. B4. B5. C6. A7. A8. B9. D10. 解析：由题设求得：， 所以当时最大。故选B二、填空题11. 12. ；13. 200914. 800三、解答题15. 解析：(1),而,；故数列是首项为，公差为1的等差数列；（2）由（1）得，则；设函数，函数在和上均为减函数，当时，；当时，；且，当趋向于时，接近1，16. 解析：（1）由已知得，又是首项为1，公差为1的等差数列；（2）由（1）知两式相减得17. 解析：()由已知得，又， 即 （2分） ，公差 由，得 （4分）即解得或(舍去) （6分）()由得 （8分） （9分） 是等差数列则
5、 (11分) (12分)18. 解析：（I）依题意，故 当时， -得：故为等比数列，且，即是等差数列（）由（I）知， （） 当时，取最小值 依题意有 解得 故所求整数的取值集合为0，1，2，3，4，5清水混凝土的配合比设计中，要针对当地水泥、砂石、外掺料及外加剂等原材料影响混凝土质量的多种因素进行分析，确定主要控制因素，并从经济性和使用要求综合考虑，优选出符合生产条件的最优方案组合。obstacles, correcting misunderstandings, advocate good cadre style. 2, adhere to the scientific decision-ma
6、king and democratic decision-making decision-making law. Correctly handle to ensure that government decrees and based on the actual creative work, giving full play to subjective initiative, put an end to implement the conference meeting, to document the implementation of documents etc. Improve the s
7、cientific and democratic decision-making mechanism, improve and implement the decision to solicit the views of experts, the public hearing system. Improve the important decision of risk assessment mechanism and legal review mechanism. 3, to promote team unity. Uphold and improve the system of annual
8、 party book talk heart to heart, mind and Party members, Party members to exchange each other not less than 2 times. The implementation of sound team democratic life system, consolidate and enhance the partys mass line educational practice will promote the achievement of the topic of democratic life
9、, criticism and self-criticism normalization, a long-term. Adhere to the party on the basis of the principle of unity, enhance internal communication, strengthen internal supervision, self Sleep maintenance team collective image and authority. (three) to ensure the execution is not strong or disguis
10、ed to resist government decrees issues. Individual Bureau leadership team members lack of learning political theory system, not from the objective reality, not with the partys interests above all the principles to deal with personal problems. In the specific work safety supervision in the execution
11、is not strong, in the implementation of the decision to deploy the discount, make choices, engage in work, the implementation of the agreement, uncomfortable is not performed, open or disguised to resist, the lack of subject consciousness of the party organization, the lack of resist in society all
12、kinds of bad habits and unwholesome tendencies of courage Gas and courage. Such as the liability insurance of safe production work, individual leaders that have someone arrested, and no funding, not in the global chess perspective to the countryside to carry out daily inspection, found none of my bu
13、siness acceptance of the resumption of production in an armchair, with a pen, indifferent. Corrective measures: (LED Leadership: Luo Mingjun, rectification time: before September 25th, insist for a long time) 1, to strengthen the sense of responsibility, work to solve the lack of decent occupation e
14、xplain away, conduct problems. To establish the overall concept, eliminate departmentalism. Strict assessment and accountability, to solve the spiritual slack, nianqingpazhong, status quo, To establish and perfect the muddle along and other issues. Bureau staff conduct work regulations, standardize the behavior of personnel. 2, strengthen the responsibility system. One is the in-depth study and implement the Hunan provincial Party and government leading cadres Interim Provisions on the work safety of a pair of (Hunan Office issued 2013 No.
