1 . 如图,已知
内接于抛物线
,且边
所在直线分别与抛物线
相切,F为抛物线M的焦点.求证:
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/27/9363e490-d4f9-4149-82da-1203d0f10886.png?resizew=200)
(1)边
所在直线与抛物线M相切;
(2)A,C,B,F四点共圆.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/854f480c60b88b546cb15d3b5622e212.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12bc980a6ff5fe01b746c65af072a05e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19409d6d120387b3bccd934c4911bb45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd646f98b097a1b09f0b8a76ec399340.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/27/9363e490-d4f9-4149-82da-1203d0f10886.png?resizew=200)
(1)边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
(2)A,C,B,F四点共圆.
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20-21高一·全国·课后作业
2 . 如图,从A点和B点测得上海东方明珠电视塔塔顶C的仰角分别为38.3°和50°(A,B两点与塔底D点在同一条直线上),
,求东方明珠电视塔的高度(精确到1m).参考数据:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e362d57cdb71a21c75eeb01e1ed85da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1afce2c04721d08936f3d1cba165d2da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e362d57cdb71a21c75eeb01e1ed85da.png)
![](https://img.xkw.com/dksih/QBM/2021/11/11/2849051998388224/2849773829677056/STEM/f3e649885e0646f3948f635dd1d1940d.png?resizew=227)
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3 . (1)若实数x,y,z满足
,证明:
;
(2)若2023个实数
满足
,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b77bd83db721327f2875fb9ce218f797.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1f921846cfd2491c21fbe42fd29fd80.png)
(2)若2023个实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52011d2f4946b2ddd070bb20796a069d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca7909872111d29739539041cb524eaf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4507435d75954f4991f50ad1376e5cb3.png)
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