已知
,
,一动点P从
开始,沿着与向量
相同的方向做匀速直线运动,速度的大小为
.另一动点Q从
开始,沿着与向量
相同的方向做匀速直线运动,速度的大小为
,设P,Q在
时分别在
,
处,问当
时,所需的时间t为多少?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b86b3ff4e6d25b7fedd7f0e86092b44c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c270787a9f4386ef278f12cfdfa28c75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6397893c31fc14f8d00a41b05b865de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ba71e05cc450bb5f2e683414c3f8fbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79f7b0630a4fe5c2d89b12ef3ee94c6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ad8acf06bc84080121faa55d579382d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94a080a6503ffba9ba042221cec21b98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79e82ad329a20a0375ffd4b55cf1797e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31f589948322f25bbae2a7de786b88c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf9f50605db5d5f8f3a01ee8e474a112.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b1698b9a76d725f9a254b9798d926fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e53fc891ae5ef554ce5f1ad0cbe9ae69.png)
更新时间:2021-12-25 11:38:15
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(1)求
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(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e2715dd9d0ec90bbe2291ee8ad4526e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc965d5374f406bcc800d140830c0d23.png)
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【推荐2】过抛物线
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【推荐1】如图所示,一条河两岸平行,河的宽度
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(1)
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(2)船在静水中速度
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f77dea92dc5b32a89ca4f2cdd6f9d8f.png)
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【推荐2】如图,已知一条河的两岸平行,河的宽度为d,某人从河的北岸出发到河对岸,河水自西向东流速为
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f44c235d8b49207ad3f2d77dc5d6cf20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/814f55724f7ee57bd395eb3b95393c68.png)
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(1)如果要使此人游得路程最短,且
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
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(2)如果要使此人游得时间最短,且
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【推荐1】如图直线l与x轴、y轴分别交于
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/24/33d7ca1f-f270-4ad8-b116-33a2eb93643d.png?resizew=137)
(1)求直线AB的方程;
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a4898591767cc2b2d6436ce215d2db4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe8a7ebf972ccc99e852ab2a4676ab12.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d59591ef74f285bb6bc6cfc85851dfe.png)
(3)在y轴上是否存在点M,使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0adf7a343c4b0ef3a3771f78489e29da.png)
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解题方法
【推荐2】已知向量
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的夹角为
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
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(1)若
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