如图1所示是放置在水平桌面上的台灯,图2是其侧面示意图,其中底座的示意图为矩形EFGB,EF=2.5cm,
,灯罩
,灯臂与底座构成的
可以绕点C下调节一定的角度.使用发现:当CD平线上方且与水平线所成的角为
时,台灯光线最佳,则将台灯调整到光线最佳时点D到桌面FG的距离为________________
(参考数据:
取1.732,结果精确到0.1cm)
![](https://img.xkw.com/dksih/QBM/2020/12/8/2616188635512832/2621204222017536/STEM/a59025c4-46ca-4317-bd82-0d17afdd000a.png?resizew=177)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0980ab28d4ee04e238f8623dcd4836f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://img.xkw.com/dksih/QBM/2020/12/8/2616188635512832/2621204222017536/STEM/a59025c4-46ca-4317-bd82-0d17afdd000a.png?resizew=177)
![](https://img.xkw.com/dksih/QBM/2020/12/8/2616188635512832/2621204222017536/STEM/d38478b998254729b618ed0a4c9606c9.png?resizew=130)
2020·山西·二模 查看更多[4]
山西2019-2020学年中考数学模拟联考试题(二)(已下线)专题15.2 锐角三角函数和解直角三角形(2)-备战2021年中考数学精选考点专项突破题集(全国通用)(已下线)1.5 三角函数的应用(重点练)-2020-2021学年九年级数学下册十分钟同步课堂专练(北师大版)(已下线)专题11 锐角的三角比及应用(考点)-备战2021年中考数学考点微专题(上海专用)
更新时间:2020-12-24 18:36:33
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