1 . 为响应“强身健体,智慧学习”倡议,复兴中学开展了一次学生体质健康监测活动.已知高三(2)班有50名学生,其中男生28人,女生22人,按男生、女生进行分层,用分层随机抽样的方法,从高三(2)班全体学生中抽取一个容量为25的样本.如果各层中按照比例分配样本,则
(1)女生应抽取的人数为_________ 人;
(2)已知样本中男生、女生的平均体重分别为
和
.估计高三(2)班全体学生的平均体重为_________
(精确到
).
(1)女生应抽取的人数为
(2)已知样本中男生、女生的平均体重分别为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bdc4d3f86e0b9d3fa58da9c9aaa55d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a625fb8d31400d4c74e7f911119c26e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24f7c4a8558eff6427d22b6c0c855721.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1cff05f157a2fbfbfbe0b9f06bff1ae.png)
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名校
2 . 若关于
的一元二次方程
有两个不相等的实数根
,且
.
(1)下列说法正确的有__________ .(将正确选项的序号填在横线上)
①若
,则
,
②
,
③若
,则
,
④若
,则
.
(2)某数学兴趣小组为了增加此题的趣味性,将题目改成:若关于
的方程
有两个不相等的实数根
,且
,其中
均为整数,则
的最小值为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92b800b7d6a688abf8a3018c133cec9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aca579894dad67bc82cb715fd48e0d70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb5ffa21fddc7c55d35f13435792b2d4.png)
(1)下列说法正确的有
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2fe3251e054fe97089806ba7033f802.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f75807858b7804a1ad2039c41f323a18.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/badd7f3edb52106b897fe62c9e9ada2e.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4d57bdb85ad21a427ebc3126fab41ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c56b1ee18c6809b339d980671b4d09a.png)
④若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a066bbbcf164565325c66d9e5f500d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc1adacd10539c74b82fc1e6e88ea6f6.png)
(2)某数学兴趣小组为了增加此题的趣味性,将题目改成:若关于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9c0dce1f975d1203a1bff7580a892d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ce7ae90d808f05e86ea063238e4b2f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097f28b6443848c98413364953c37ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
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3 . 如图,
两点在双曲线
上,
两点在双曲线
上,若
轴,且
,则
的面积为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6114947179bed8c2c86ac078e2f8497f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2311a0e8fe086ac4bfa89b75417da00b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20ebaa32f4f1f4f807ca9aeb7fb29951.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db27d050c1f126c5b94b2e3b22a14f35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20cd2fd2fbb51a162b1054b531daaa9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b417db3873f3e6d0e9cd235a4ef685a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4807ca16360c0cca436e59d4be98f626.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/22/221ac969-cb33-47cb-bbd6-b6a29bd9c582.png?resizew=160)
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4 . 设
,
为正整数,若
,则(1)
的一个可能的值为_______ ;(2)与(1)中
的值相对应的
的值为_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e73c2d6bc5b1b2f95b5843d3d2a78c49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
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