名校
解题方法
1 . 如图,在三棱锥
中,平面
平面
,
为等边三角形,
,且
,E,F分别为AC,PC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/27/c686e2c5-6be9-4775-91ee-9d49f55350b7.png?resizew=183)
(1)求证:
平面
;
(2)求证:平面
平面
;
(3)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fbfcae2cecc98e2d6c16dde6d3ec1c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb4957406b21df59fdf7fa184752287b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/27/c686e2c5-6be9-4775-91ee-9d49f55350b7.png?resizew=183)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/373f735f0f04d11f1951eaef1bb78b6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87c0bfeadcf17b2a45896071f07a4a5a.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e51838e395dfc9d9ef597d9e01f46272.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(3)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
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解题方法
2 . 选修4-5:不等式选讲
(1)设
,证明:
;
(2)已知
,证明:
.
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ada798eeba5bd19d497bfd0741afd00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94aa428b8f14ca9cefe41eb4e44244fc.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d2acd1e0e18c3be37a458b8e35811f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/931b0673c08a4b6b58811d0b68c4daf2.png)
您最近一年使用:0次
解题方法
3 . 已知数列
的前
项和为
,
,其中
为常数.
(1)证明:
;
(2)是否存在
,使得
为等差数列?并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be4243663d7018f638485e8f34e04dcd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed614ed42c70449680512edc6cbe83de.png)
(2)是否存在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
您最近一年使用:0次