1 . (原创)在非直角
中,
为
上的中点,且
,
为边
上一点,
,
,则
的面积的最大值为__________ .(其中
表示
的面积)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82b8f94d6fd005534d064ddacf8800b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcbd3835acdb0c946b5fc3c5a3f3b0f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60634341a9603e24b2bbc6960abe3d31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58195e8ee6f342c1641d9e88ff986f56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
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2017-05-27更新
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2卷引用:重庆市第一中学2016-2017学年高一下学期期中考试数学试题
名校
解题方法
2 . 把平面图形
上的所有点在一个平面上的射影构成的图形
叫做图形
在这个平面上的射影.如图,在三棱锥
中,
,
,
,
,
,将围成三棱锥的四个三角形的面积从小到大依次记为
,
,
,
,设面积为
的三角形所在的平面为
,则面积为
的三角形在平面
上的射影的面积是
![](https://img.xkw.com/dksih/QBM/2017/3/28/1653753087377408/1656596902756352/STEM/07c1669bb07b4feb900e77cb2c3a00f2.png?resizew=286)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da895d8bd043625a0839128252130d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e7796caec20ab20a46b31f36a188392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73cab28475a885ff0b5b5d947d65b5ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a8739cc8fc1570400f30f5af109a025.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a1100f8c8bd07c7dfc3c29991acf00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca201616362528f3615de6edb2317848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b56d35b0e69e306a453c5226899c71c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d43eb0b274e00cbbc4a210da4165042.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/530f5b63e797195906285c0c03eb9276.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83c2d5971afbff8eca1b9aff5f76f710.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e204eeda3cbe67e9e709be5c790b49f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/530f5b63e797195906285c0c03eb9276.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e204eeda3cbe67e9e709be5c790b49f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://img.xkw.com/dksih/QBM/2017/3/28/1653753087377408/1656596902756352/STEM/07c1669bb07b4feb900e77cb2c3a00f2.png?resizew=286)
A.![]() | B.![]() | C.![]() | D.![]() |
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2017-04-01更新
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1845次组卷
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6卷引用:2017届四川省成都市高三第二次诊断性检测数学理试卷
2017届四川省成都市高三第二次诊断性检测数学理试卷河北省衡水市衡水中学2019届高三下学期六调考试(文)数学试题(已下线)【全国百强校】河北省衡水中学2019届高三下学期六调考试数学(文)试题(已下线)专题8.6 空间直线、平面的垂直(一)【八大题型】-举一反三系列四川省泸县第五中学2022-2023学年高三上学期第三学月考试数学(理)试题重庆市万州第二高级中学2023届高三三诊数学试题
3 . 一台风中心于某天中午12:00在港口
的正南方向,距该港口
千米的海面
处形成(如图),并以每小时
千米的速度向北偏东
方向上沿直线匀速运动,距台风中心
千米以内的范围将受到台风的影响,请建立适当的坐标系.
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/e2411f85b0ff4b929d127e4082085db2.png)
(1)当台风中心离港口
距离最近时,求该台风所影响区域的边界曲线方程;
(2)若港口
于当天下午17:00开始受到此台风的影响,(i)求
的值;(ii)求港口
受该台风影响持续时间段的长.
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/cad9541cbf1c4c4db8e7f7672c319be2.png)
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/7c56421c378549ddaadc08061dbfb6a2.png)
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/7d4e72dd473b40aba6d262e698be28c6.png)
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/a22c0916988d492a8f67c6291d768997.png)
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/fb5f999fff054b818140d7f103523bad.png)
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/2003a83b4cf64afca0e62d7df56e9933.png)
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/e2411f85b0ff4b929d127e4082085db2.png)
(1)当台风中心离港口
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/cad9541cbf1c4c4db8e7f7672c319be2.png)
(2)若港口
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/cad9541cbf1c4c4db8e7f7672c319be2.png)
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/a22c0916988d492a8f67c6291d768997.png)
![](https://img.xkw.com/dksih/QBM/2016/7/4/1572876590702592/1572876596994048/STEM/cad9541cbf1c4c4db8e7f7672c319be2.png)
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