名校
1 . 如图所示,合肥一中积极开展美丽校园建设,现拟在边长为0.6千米的正方形地块
上划出一片三角形地块
建设小型生态园,点
分别在边
上.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/71886729-eb46-4b62-9618-1ccb10024ad5.png?resizew=135)
(1)当点
分别时边
中点和
靠近
的三等分点时,求
的余弦值;
(2)实地勘察后发现,由于地形等原因,
的周长必须为1.2千米,请研究
是否为定值,若是,求此定值,若不是,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70db40c42655327adee01caedfc9d50c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9df7fc746f8c4801d8f2f0471ba3297e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/71886729-eb46-4b62-9618-1ccb10024ad5.png?resizew=135)
(1)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52f8eff113ca3f0d0200253c7c2f5a7a.png)
(2)实地勘察后发现,由于地形等原因,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5a9fc2dda89829fa2c610a8fce86d22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52f8eff113ca3f0d0200253c7c2f5a7a.png)
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2019-10-14更新
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3卷引用:辽宁省六校协作体2020-2021学年高一下学期期中数学试题