解题方法
1 . 如图,直角梯形ABCD中,
,直角梯形ABCD绕BC旋转一周形成一个圆台.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/27/178702ac-c60a-406b-9084-27666badbbec.png?resizew=197)
(1)求圆台的表面积和体积;
(2)若直角梯形ABCD绕BC逆时针旋转角
到
,且直线
与平面ABCD所成角的正弦值为
,求角
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a1da73b7d511136cd82053728e0a02f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/27/178702ac-c60a-406b-9084-27666badbbec.png?resizew=197)
(1)求圆台的表面积和体积;
(2)若直角梯形ABCD绕BC逆时针旋转角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5766292c7ff8834141e424796ad8e08f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7775df7ba0dc94c15e9e706194a463f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10d8eb4a9f462ca0c1d49c3fe91e720d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3aace91caec728e174daec29a3568ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
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