1 . 在一个特定时段内,以点
为中心的7海里以内海域被设为警戒水域,点
正北55海里处有一个雷达观测站
,如图所示.某时刻测得一艘匀速直线行驶的船位于点
北偏东
且与点
相距
海里的位置
,经过40分钟又测得该船已行驶到点
北偏东
(其中
)且与点
相距
海里的位置
.
(2)若该船不改变航行方向继续行驶,判断它是否会进入警戒水域?如果会,大约会在警戒水域行驶多少海里?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/270800ba975e87235e8802a631e5f3a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c05185a60d5d37c5af32ffea71066b1c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fc8683acdb0ff28b06ba96716cf9d63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40d3413e1978040c5e98cb463464f56f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a196a5dbd7c7661eca3d1fb4af0f3651.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)若该船不改变航行方向继续行驶,判断它是否会进入警戒水域?如果会,大约会在警戒水域行驶多少海里?
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解题方法
2 . 如图,四边形
是一块长方形绿地,
是一条直路,交
于点
,交
于点
,且
.现在该绿地上建一个标志性建筑物,使建筑物的中心到
三个点的距离相等.以点
为坐标原点,直线
分别为
轴建立如图所示的直角坐标系.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/4/0e9e3945-adeb-43d3-979c-bf54370f24e6.png?resizew=121)
(1)求出建筑物的中心的坐标;
(2)由建筑物的中心到直路
要开通一条路,已知路的造价为100万元/
,求开通的这条路的最低造价.附:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b18640d06d12c8778c043dec50d9802.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1774c622c5f84e205d5792f7655d14f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/927456b0989846a2f1573844bbaa2105.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3676391efa2ac62958c633b7943e746.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/4/0e9e3945-adeb-43d3-979c-bf54370f24e6.png?resizew=121)
(1)求出建筑物的中心的坐标;
(2)由建筑物的中心到直路
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5fe30c67ac20cd4e8b9cc2d0d420a7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d92accf6e50007ee4b73b16487f78a.png)
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