2021届山东省烟台市高考一模（诊断性测试）数学试题（可编辑PDF版）

高三数学参考答案（第 1页，共 6页） 2021 年高考诊断性测试 数学参考答案 一、单选题 BDCC BADD 二、多选题 9.ABC 10.BD 11.BC 12.ACD 三、填空题 13. 2 2 14.1.75 15.[1 3 3, )  16. 5 6 四、解答题 17.解：若选①:（1）由已知 2 2 1 2b T T   ， 3 3 2 4b T T   ， 所以 3 2 2bq b   ，通项 2 2 12 2 2 2 n n n nb b q       .··········································2 分 故 1 1 1a b  .···························································································3 分 不妨设{ }na 的公差为 d .则1 2 1 4 14d d    ，··············································4 分 解得 2d  ， 所以 2 1na n  .····································································· 6 分 （2）由 [lg ]n nc a ，则 1 2 3 4 5 0c c c c c     ， 6 7 50 1c c c     ， 51 52 100 2c c c     ，·············································································9 分 所以 1 2 3 100c c c c      1 45 2 50 145    .···········································10 分 若选②:（1）由已知 2 2 1 2b T T   ， 3 3 2 4b T T   ， 所以 3 2 2bq b   ，通项 2 2 12 2 2 2 n n n nb b q       .··········································2 分 故 1 1 1a b  .···························································································3 分 不妨设{ }na 的公差为 d，则 4 34 1 28 2 d    ，···········································4 分 解得 4d  ，所以 4 3na n  ．·····································································6 分 （2）由 [lg ]n nc a ，则 1 2 3 0c c c   ， 4 5 25 1c c c     ， 26 27 100 2c c c     ，············································································ 9 分 所以 1 2 3 100c c c c      1 22 2 75 172    .···········································10 分 若选③:（1）由已知 2 2 1 2b T T   ， 3 3 2 4b T T   ， 所以 3 2 2bq b   ，通项 2 2 12 2 2 2 n n n nb b q       .··········································2 分 故 1 1 1a b  .···························································································3 分 不妨设{ }na 的公差为 d，则 2(1 7 ) (1 4 )(1 12 )d d d    ，································· 4 分 因为 0d  ，