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解题方法
1 . 如图,圆柱
中,
、
分别为圆
、圆
的直径,
为母线,
,点
在上底面的圆
内,点
在弧
上.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/13/5202acbe-9ebd-40a5-a5fc-503b15f6ffd8.png?resizew=130)
(1)求三棱锥
的体积的最大值;
(2)求三棱锥
的外接球的体积的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/192f4f9446c954a291f779d963f90257.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27db558e8db4c957654c8e5cecd2d2dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/13/5202acbe-9ebd-40a5-a5fc-503b15f6ffd8.png?resizew=130)
(1)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5ad3f3235cad0699a2dbcce65c62770.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5ad3f3235cad0699a2dbcce65c62770.png)
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2 . (1)如图1,正四棱锥
,
.
(ⅱ)
为
上一点,求
的最小值;
(2)将边长为4a的正方形铁皮用剪刀剪切后,焊接成一个正四棱锥(含底面),并保持正四棱锥的表面与正方形的面积相等,在图2中用虚线画出剪刀剪切的轨迹,并求焊接后的正四棱锥的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82465b63174087aeba7788ed984583d2.png)
(ⅱ)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa4bd24cd9e80854a6345e4ef9cf5da6.png)
(2)将边长为4a的正方形铁皮用剪刀剪切后,焊接成一个正四棱锥(含底面),并保持正四棱锥的表面与正方形的面积相等,在图2中用虚线画出剪刀剪切的轨迹,并求焊接后的正四棱锥的体积.
您最近一年使用:0次