如图,四边形ABCD是圆柱的轴截面,
,O分别是上、下底面圆的圆心,EF是底面圆的一条直径,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/c5c9bfff-a4f4-4a38-b1db-8604bc8efcce.png?resizew=168)
(1)证明:
.
(2)若
,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12fe32dfbd66709875c5b9f79c9496da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7faabc484ce3666706c1beffda4bcfe2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/c5c9bfff-a4f4-4a38-b1db-8604bc8efcce.png?resizew=168)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab00e0cff0876c4183a47f1272cf9928.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0573047d36d2945d6e474bdf051db1a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec66c1d36c6c2be3d3fc4519dfca195e.png)
更新时间:2022-03-26 09:52:03
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解题方法
【推荐1】在①
,②
,③
.三个条件中任选一个,补充在下面的问题中,并解决该问题.
在
中,角A,B,C的对边分别为a,b,c,且满足,
.
(1)求角C;
(2)求
周长的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/254ccc9afb6437639310a0ff8ad2d5ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08b4674dbfd583bbbc5f0c33b940eb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abe18705f1acfb8c0a5897d6ebfd3557.png)
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6de1d395e6c48c0676a1488a299479d9.png)
(1)求角C;
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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【推荐2】在
中,角
所对的边分别为
,且
.
(1)求角
的值;
(2)若
,
的面积为
,求
的周长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aeac01cbfca4071ff96f9192df7754e5.png)
(1)求角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e258ab9e600435b37465092243d99f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/860884c0017c8bceb5b0edff796c144f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
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【推荐1】《九章算术》是中国古代的一部数学专著,是《算经十书》中最重要的一部,是当时世界上最简练有效的应用数学,它的出现标志着中国古代数学形成了完整的体系.《九章算术》中将由四个直角三角形组成的四面体称为“鳖臑”,已知四面体
是“鳖臑”,
,
,
,
分别为
,
的中点,
在线段
上,且
.
平面
;
(2)求四面体
内切球的表面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bae7599ad243c12d94325ad917f0a44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080ca48cd27d4bf9d9ef084b558fc17a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c3764c14968ed67e0be113ad6b9cfbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a619288429fb6f75cc51f6c7fa43d03a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b8f7c29e731da1ee3afa138c76cd3e1.png)
(2)求四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
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名校
【推荐2】如图,三棱锥
中,
为等边三角形,
为
的中点
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/e70b8b18-51cf-4912-8c08-782ba711a643.png?resizew=152)
(1)求证:
平面
;
(2)设
,若
,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7df6d51738ac1bc8b9530ea4a55745c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6946cf93748839de2f2862629985676b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/e70b8b18-51cf-4912-8c08-782ba711a643.png?resizew=152)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97f30533da2e1d2a958dc906c37eba9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/082c35d1a4be3d522a98d9116370384a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e3f5dc11efe60b4fd9a13b1d6b83842.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
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【推荐1】如图,四棱锥
的底面是边长为2的正方形,
底面
,
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/8/1806ce99-e75e-46c3-b489-bc2a6642469a.png?resizew=208)
(1)求异面直线
与
所成的角;
(2)在底边
上是否存在一点
,使
平面
?证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37e2267c84394668eff2e9f5918de4fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/8/1806ce99-e75e-46c3-b489-bc2a6642469a.png?resizew=208)
(1)求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
(2)在底边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a5f445af1ae136773cb338920552ff2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
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解题方法
【推荐2】如图所示,四边形ABCD是边长为3的正方形,DE⊥平面ABCD,求证:AC⊥BE
![](https://img.xkw.com/dksih/QBM/2021/8/1/2776929645928448/2821942425346048/STEM/bf6db25024fe4689ada63bffd81d7d4c.png?resizew=238)
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解题方法
【推荐1】如图,三棱柱
中,侧面
为菱形,
,且
.
![](https://img.xkw.com/dksih/QBM/2022/3/19/2939720919900160/2940246458777600/STEM/10bfaeb129ce4687a0fe0f4a5adf508b.png?resizew=246)
(1)证明:
;
(2)若
,
,
,求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9778ae9823e8430d73d87c57fc47b185.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8db87b41df9d3c83d2810a4265d768d3.png)
![](https://img.xkw.com/dksih/QBM/2022/3/19/2939720919900160/2940246458777600/STEM/10bfaeb129ce4687a0fe0f4a5adf508b.png?resizew=246)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00ee347187fbbfe9e8a6faf286795d79.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c7fd49bb962841b4575805030e19add.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f2e238b2757353026133bbe495645e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/829018a6ca0aff95d89e3f7cd943274e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
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解答题
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适中
(0.65)
【推荐2】如图,在四棱锥
中,
平面
.
![](https://img.xkw.com/dksih/QBM/2017/2/16/1625395377651712/1626610373746688/STEM/ff04d0685e0747c88ddde0ff7b67e92e.png?resizew=154)
(1)在线段
上确定一点
,使得平面
平面
,并说明理由;
(2)若二面角
的大小为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d02bd5cfe804460846423e77f72db10f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb4564baf209de77802d46cda82995c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe2a34cad3f682ead64c759e2c829b7f.png)
![](https://img.xkw.com/dksih/QBM/2017/2/16/1625395377651712/1626610373746688/STEM/ff04d0685e0747c88ddde0ff7b67e92e.png?resizew=154)
(1)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88929f4ba0851730d5f941d426b87548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f85db6f28f09fe9382a3ba571875f8c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3520ee9cc97a075e889e1625dba1157c.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/367d22bde85bae176f3847faacfb2c8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe8140a38ee6b0b28a5b661f8b1f3d5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/085aa19f9f63f7a98e75c433edf25679.png)
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