2024年12月诊断数学答案.pdf

202412

标准学术能力诊断性测试年月测试

数学参考答案

8540

一、单项选择题：本题共小题，每小题分，共分．在每小题给出的四个选项中，只有一项是

符合题目要求的．

12345678

DDACCACA

二、多项选择题：本题共3小题，每小题6分，共18分．在每小题给出的四个选项中，有多项符合

题目要求．全部选对的得6分，部分选对但不全的得3分，有错选的得0分．

91011

CDABABC

三、填空题：本题共3小题，每小题5分，共15分．

25

12．−13．或14．(−，0

10612

577

四、解答题：本题共小题，共分．解答应写出文字说明、证明过程或演算步骤．

1513

．（分）

解：（1）S33a2−15，所以a2=−5······································································2分

因为a1=−7，所以公差d=2······································································4分

得a=−7+2n−12·······································································6分

n()=n−9

*

（2）因为对任意nN，都有SnS7，

所以SS,SS，得a0,a0··························································2分

876787

由（1）知a2=−5，所以a8a2=+6d=−5+6d0,a7=−5+5d0·················5分

5

得d1······························································································7分

6

1615

．（分）

解：（1）因为，不在平面PCD内，所以平面PCD··························2分

ABCDABAB