2024届四川省绵阳市高三上学期第一次诊断性考试 理数答案

3.0 envi 2024-11-26 6 4 199.34KB 7 页 3知币
侵权投诉
绵阳市高中 2021 级第一次诊断性考试
理科数学参考答案及评分意见
一、选择题：本大题共 12 小题，每小题 5分，共 60 分．
BCDAC ADBBD CC
二、填空题：本大题共 4小题，每小题 5分，共 20 分．
13．7 14． 15．9
16．1
三、解答题：本大题共 6小题，共 70 分．
17．解：（1）由 a1，a2，a4成等比数列，则 ，································2 分
∴，
可解得 ，··················································································3 分
∴数列{an}的前 项和 ；·······························5 分
（2） ①，···············································6 分
当 时， ，可得 ,·······················································7 分
可得 ②，·····································································8 分
由②式－①式，得 ，············································9 分
∴
······································································11 分
．························································································12 分
1
8．解：（1）∵ ，则 ，·····················································1 分
又
，··························································2 分
∴
，·······················································································4 分
∴
；·······································································5 分
（2）
由题意， ，···················································6 分
∵
·································································7 分
∴
·····································8 分
∴
Z，·····························································9 分
∴
，····················································10 分
∴的最小值为 ．·········································································12 分
19．解：（1）∵ 为奇函数，
∴，解得：m=2．··························································5 分
（2）当 m>0 时，2x2+m>0 ，
∴函数 不可能有两个零点．·······························6 分
当m <0 时，由 ，解得： 或 m2，·································7 分
要使得 f(x)仅有两个零点，则 ，·········································8 分
即 ，此方程无解．
故m=0，即 ，······························································9 分
令 ，则 ，
，解得： 或 ， 解得： ，
故 在 ， 上递增，在 上递减，···························10 分
又 ，
故函数 仅有一个零点．························································12 分
20．解：（1）∵cos(CB)sinA=cos(CA)sinB
∴
(cosCcosB+sinCsinB)sinA=(cosCcosA+sinCsinA)sinB································2 分
∴cosCcosBsinA=cosCcosAsinB······························································3 分
又∵△ABC 为斜三角形，则 cosC≠0，
cos∴BsinA=cosAsinB，········································································5 分
sin(∴AB)=0，又 A，B为△ABC 的内角，
∴A=B；··························································································6 分
（2）
由△ABC 的面积 S= ，
∴S= absinC= ，则 bsinC=1，即 =sinC，·········································7 分
2024届四川省绵阳市高三上学期第一次诊断性考试 理数答案.docx

共7页,预览3页

还剩页未读， 继续阅读

相关推荐

更多
立即下载
作者：envi 分类：分省 价格：3知币 属性：7 页 大小：199.34KB 格式：DOCX 时间：2024-11-26

开通VIP享超值会员特权

  • 多端同步记录
  • 高速下载文档
  • 免费文档工具
  • 分享文档赚钱
  • 每日登录抽奖
  • 优质衍生服务

作者详情

相关内容

更多

推荐作者

热门标签

大联考 高考地理 英语真题 听力 语法填空 石家庄 数学竞赛 读后续写 英语阅读 深圳中学
/ 7
评分 收藏
分享
立即下载
客服
关注