内容正文:
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市质检数学(文科)参考答案与评分标准 第 1 页(共 10 页)
泉州市 2020届普通高中毕业班第一次质量检查
数学(文科)参考答案与评分标准
评分说明:
1.本解答给出了一种或几种解法供参考,如果考生的解法与本解答不同,可根据试题的主要考
查内容比照评分标准制定相应的评分细则.
2.对计算题,当考生的解答在某一步出现错误时,如果后继部分的解答未改变该题的内容和难
度,可视影响的程度决定后继部分的给分,但不得超过该部分正确解答应给分数的一半;如果后继部
分的解答有较严重的错误,就不再给分.
3.解答右端所注分数,表示考生正确做到这一步应得的累加分数.
4.只给整数分数.选择题和填空题不给中间分.
二、填空题:本大题共 4小题,每小题 5分,共 20分.将答案填在答题卡的相应位置。
13.2 14. ),0[ 15.2 3 2 ,
14π
3
16.2.
三、解答题:共 70分。解答应写出文字说明,证明过程或演算步骤。第 17~21题为必考题,每个试题考
生都必须作答。第 22、23题为选考题,考生根据要求作答。
(一)必考题:共 60分。
17.【命题意图】本题主要考查数列 na 与 nS 的关系、等比数列的通项公式、前 n项和公式等基础知识,考
查运算求解能力,考查化归与转化思想、分类与整合思想,考查发展数学抽象、数学运
算及数学建模等核心素养.
解:(1)当 1n 时, 1 1 1a S ,······················································································· 1分
当 2n≥ 时, 1n n na S S ······················································································ 2分
2 2( 1)n n ·················································································· 3分
2 1n ,······················································································· 4分
因为 1 1a 适合上式,························································································· 5分
所以 2 1na n ( N )n .················································································· 6分
(2)由(1)得 1 1b , 3 9b ,················································································ 7分
设等比数列{ }nb 的公比为 q,则
2
3 1 9b b q ,解得 3q .··································8分
市质检数学(文科)参考答案与评分标准 第 2 页(共 10 页)
当 3q 时, 1 (1 3 ) 3 1
1 3 2 2
n n
nT
,······························································· 10分
当 3q 时, 1 [1 ( 3) ] 1 ( 3)
1 ( 3) 4 4
n n
nT
.····················································· 12分
17 评分补充说明:
(1)问:
①“因为 11 a 适合上式”这句话没写不扣分;但如果没有求 11 a 的,要扣 1 分;
②用不完全归纳法求出 12 nan 的,得 3 分;
(2)问:
①如果只求出 3q ,后面只求出
2
13
n
nT 一种情况的,得 3 分;
②如果因为第 1 问出错,导致求的 nb 也出错,但后续解法正确的话,根据实际情况,给不超过 3 分。
18.【命题意图】本题考查统计图表、频率与概率的关系、用样本估计总体、独立性检验等知识点.考查
了学生对统计图表的识读与计算能力,考查了学生的数学建模、数据