1 . 如图,在四面体
中,
,则四面体
体积的最大值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dffb760397e3b46f1412aa0d5b42c295.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/16/d7d18cf2-cf5e-499b-833f-059d0aff00f9.png?resizew=153)
您最近一年使用:0次
2023-09-30更新
|
658次组卷
|
3卷引用:河北省保定市2023届高三二模数学试题
2 . 在平面内,若曲线
上存在点
,使点
到点
,
的距离之和为10,则称曲线
为“有用曲线”,以下曲线是“有用曲线”的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/241ce9bd28046ce9b90f43b391132884.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8314b1fdf7dcef270ac0a2567609242.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
3 . 下列命题中
①已知点
,动点
满足
,则点
的轨迹是一个圆;
②已知
,则动点
的轨迹是双曲线右边一支;
③两个随机变量的线性相关性越强,则相关系数的绝对值就越接近于
;
④在平面直角坐标系内,到点
和直线
的距离相等的点的轨迹是抛物线;
⑤设定点
,动点
满足条件
,则点
的轨迹是椭圆.
正确的命题是__________ .
①已知点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c2ba05abdc8179e5ff980fb2d15ce2a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71dfa562fe8529f0f92673c2864d3c5d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
②已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57e60f7f44e7986a067b75c53faa438f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
③两个随机变量的线性相关性越强,则相关系数的绝对值就越接近于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
④在平面直角坐标系内,到点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c832f2474efe89961ef41e884da7660c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ff16f02559e1312c183861c5526e560.png)
⑤设定点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8946b9552dc83bced9cfc7d8909f8d86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fde9ba55ec6f59344a2a68f9b32f7c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
正确的命题是
您最近一年使用:0次
2017-12-05更新
|
970次组卷
|
2卷引用:河北省定州市2017-2018学年高二上学期期中考试数学(理)试题