1 . 已知圆锥的轴截面是正三角形,求证:它的侧面积是底面积的2倍.
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2020-01-31更新
|
240次组卷
|
3卷引用:第十一章 立体几何初步 本章小结
解题方法
2 . 如图,在圆锥
中,已知
,圆
的直径
,
是弧
上的点(点
不与
、
重合),
为
中点
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/22/bfaf9b63-c37b-4822-b1f2-ceb10713365a.png?resizew=168)
(1)求圆锥
的侧面积;
(2)证明:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef49a3ca580a144cc65a609c167facc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e89e99ab9c1ece0cc5c3bbabaa97de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/22/bfaf9b63-c37b-4822-b1f2-ceb10713365a.png?resizew=168)
(1)求圆锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef49a3ca580a144cc65a609c167facc1.png)
(2)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3da05ded8b60b97142b4d975ffe782c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
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