解题方法
1 . 如图,直四棱柱
中,
分别为
的中点,
,
,
.
(1)求证:
平面
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c6d9ef8efe6b947b6f5aa1ee95cd5f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84e0b7d845cbceccd3e76ca461fcc534.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a50943279ee6f0299b3725eecd77bafd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7dbf31dfd36aa456a63bafea8bc1985.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/29/5106f5ed-ccaa-4275-9972-2e879f310ada.png?resizew=149)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06222ee533c2484ab25321a6abbf98cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1651bb032aa531a7aca3bc61e6a045d5.png)
您最近一年使用:0次
解题方法
2 . 设△ABC的内角A,B,C所对的边分别为a,b,c,
,且
.
(1)求证:
;
(2)求△ABC面积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79998787e2d78b13494915896c446d19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b409809543bae9f5e231a83e515dbbf.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a66cbc9e5601178878c36c4f744bffa1.png)
(2)求△ABC面积的最大值.
您最近一年使用:0次