解题方法
1 . 求证:斜棱柱的侧面积等于它的直截面(垂直于侧棱并与每条侧棱都相交的截面)的周长与侧棱长的乘积.
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2 . 蜂房是自然界最神奇的“建筑”之一,如图1所示.蜂房结构是由正六棱柱截去三个相等的三棱锥
,
,
,再分别以
,
,
为轴将
,
,
分别向上翻转
,使
,
,
三点重合为点
所围成的曲顶多面体(下底面开口),如图2所示.蜂房曲顶空间的弯曲度可用曲率来刻画,定义其度量值等于蜂房顶端三个菱形的各个顶点的曲率之和,而每一顶点的曲率规定等于
减去蜂房多面体在该点的各个面角之和(多面体的面角是多面体的面的内角,用弧度制表示).
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/a92b50df-d218-42a5-9a1b-745e46427d6b.png?resizew=452)
(1)求蜂房曲顶空间的弯曲度;
(2)若正六棱柱的侧面积一定,当蜂房表面积最小时,求其顶点
的曲率的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/653c6425ba284719913a5ba89b76d148.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d22678c6aa7bc1b372fa8f46a596be59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db8eccace9994691c9219e098b574c65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1642eec556eb252de9c1ab7bb5ca90b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17eba1a234a34ceeb44bcd15216a2866.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d218d925d9bdfbafd000c5cbd7787d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5ec26174ee387a474d3e264ff2e9205.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfe639eab78eafd2d40ea70aa5d3f21d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67716ac738ee2911a69bf4063110a5bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e9fdc1f8ed0ae44b54a9a2a3aca2db4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/a92b50df-d218-42a5-9a1b-745e46427d6b.png?resizew=452)
(1)求蜂房曲顶空间的弯曲度;
(2)若正六棱柱的侧面积一定,当蜂房表面积最小时,求其顶点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
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