名校
解题方法
1 . 已知任意三角形的三边长分别为
,内切圆半径为
,则此三角形的面积可表示为
.其原理是由内切圆的圆心与三角形三个顶点的连线把三角形分割成三个小三角形,每个小三角形的面积等于大三角形的边长与内切球半径的乘积的
,三个小三角形面积相加即得
.请运用类比思想,解决空间四面体中的以下问题.
(1)已知四面体四个面的面积分别为
,
,
,
,内切球的半径为
,请运用类比思想,写出该四面体的中的相应结论;
(2)应用(1)中的结论求解:已知三棱锥(又叫四面体)
,三条侧棱
,
,
两两垂直,且
,求此三棱锥的内切球半径.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11bc05f41215f9894e11d1df0465751a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53d69e0bbde9001538ffea1063d11db7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1c011c6b72ee4888607e272e2168178.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/13/ff37a84b-8751-4101-a6e8-7c7a4b05469a.png?resizew=147)
(1)已知四面体四个面的面积分别为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6899bf9cadae2ccdb14cbc87d4f280ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f30f56664446f32dbbc2c5f12a99374.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aa0df7f1e45f9de29e802c7f19a4f64.png)
(2)应用(1)中的结论求解:已知三棱锥(又叫四面体)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50094bfee564d9c1b03088ac2ece28c3.png)
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2 . 高一某班级共有
行
列个座位,记为
.每周进行一次轮换,轮换规则如下:①每一行轮换到下一行,最后一行轮换到第一行;②从左到右,每一列轮换到相邻右边一列,最后一列轮换到左侧第一列.例如,班级共有
个座位,则本周第3行第4列的同学,在下周一将轮换到第4行第5列的座位.现某班的座位形式为
,经过推演发现,如果一直按这种轮换法,在高中三年内每一个学生都可以轮换到全班所有座位,则
可能为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0abc7b7ef8b7a91099ca63ea1aaf7cfa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/355bc0d6058a3dd1254ff395176ec55b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0abc7b7ef8b7a91099ca63ea1aaf7cfa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0abc7b7ef8b7a91099ca63ea1aaf7cfa.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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解题方法
3 . 我们知道,在平面中,给定一点和一个方向可以唯一确定一条直线.如点
在直线l上,
为直线l的一个方向向量,则直线l上任意一点
满足:
,化简可得
,即为直线l的方程.类似地,在空间中,给定一点和一个平面的法向量可以唯一确定一个平面.
(1)若在空间直角坐标系中,
,请利用平面
的法向量求出平面
的方程;
(2)试写出平面
(A,B,C不同时为0)的一个法向量(无需证明),并证明点
到平面
的距离为
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1dab74e16403e8131f9f5b2a74f3a84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f41c46212d6f61fca9ce215a477ea1d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdfc3eef2f592a4e93a6968c7f31e32f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e463b86ed390c317de2383840fde5df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a24f3197942ff7bd44f44651dd9123b2.png)
(1)若在空间直角坐标系中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3ad64b23e508734de034ce16e1ebbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22ce50ba5e349425274f05d46d120a74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22ce50ba5e349425274f05d46d120a74.png)
(2)试写出平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a46e2fbcd9ba92ca62a67fef9d9652db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab9f353152c7f589c0caf5f964f803ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39f20004bf3d4eb52ec732d8acc65672.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e878d6f51b5830bd59f0d44aa5d8b38.png)
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2023高三·上海·专题练习
4 . 设等差数列
的前
项和为
,则
、
、
成等差数列.类比研究等比数列有下面三个命题:
①设等比数列
的前
项的和为
,则
、
、
成等差数列;
②设等比数列
的前
项的和为
,则
、
、
成等比数列;
③设等比数列
的前
项的积为
,则
、
、
成等比数列;
④设等比数列
的前
项的积为
,则
、
、
成等比数列.
其中真命题的个数是( )
![](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/0f30f56664446f32dbbc2c5f12a99374.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1b0ed9533c1ea30a87249539a005e62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/648d3aceec8f1aff90191c20d7e51b2f.png)
①设等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87bd7d18f67e90a7c37fad4252e43c9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91c08ee3ab8b691825d94fdb448868ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93b8b635d49a4a4beaf2c49d441352b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f214c8f5adbeb64d40ea387cec4d5f13.png)
②设等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87bd7d18f67e90a7c37fad4252e43c9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91c08ee3ab8b691825d94fdb448868ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93b8b635d49a4a4beaf2c49d441352b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f214c8f5adbeb64d40ea387cec4d5f13.png)
③设等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2114a0fe21dc0e5bf831c146ef02b113.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6dce0bc27993c08918cdffddcdee852.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0e39ed6588243d88450ec3ca4f0e9f1.png)
④设等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2114a0fe21dc0e5bf831c146ef02b113.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7874208f32aeebb6ceaa2571408d9197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e2b24dbedb33be54b8095893f111cbb.png)
其中真命题的个数是( )
A.![]() | B.![]() | C.![]() | D.![]() |
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5 . 对于三元基本不等式请猜想:设![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec197b8ab457cfee3d4733f3d7f8d6f3.png)
_________ ,当且仅当
时,等号成立(把横线补全).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec197b8ab457cfee3d4733f3d7f8d6f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44acc0ee22dc4b7750e8be825e7c1355.png)
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6 . 给出下列类比推理命题,其中类比结论正确的是( )
A.由“已知a,b为实数,若![]() ![]() ![]() ![]() |
B.由“已知a,b,c为实数,若![]() ![]() ![]() ![]() ![]() ![]() ![]() |
C.由“在平面内,若直线a,b,c满足![]() ![]() ![]() ![]() ![]() ![]() |
D.由“若圆O的半径为r,则圆O的面积为![]() ![]() |
您最近一年使用:0次
2022-07-06更新
|
124次组卷
|
2卷引用:河南省南阳地区2021-2022学年高二下学期期终摸底考试文科数学试题
7 . 已知函数
有两个零点
,则可设
,由
,所以
,
,这就是一元二次方程根与系数的关系,也称韦达定理,设多项式函数
,根据代数基本定理可知方程
有
个根
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/331d5e308cd5469e0f28a8d75f79903f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ce7ae90d808f05e86ea063238e4b2f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e38a748661547c23dc5bb7727157a272.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cce519ecad53af16de6b8fa9434110e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f05dd02b6f561dcf94bab8a3160108d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/897630dd340ec6c6b20cdd754d0a12c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3bdb2ad96ef43cf5e427d7a2d9fafe4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86b92b70365c63607daecdc8deb73ecf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c83590c4a7ea5636843dd4b60c67cb40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a0a7f3b30ea5e3955d435792fa71698.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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名校
8 . 对任意两地
,
,若其同一周的空气质量指数分别为
,
,
,
,
,
,
与
,
,
,
,
,
,
,设集合
,若集合
中元素个数大于等于4,则称
这一周的空气质量优于
的空气质量,记为
.现考虑
,
,
三地某周的空气质量指数,下列说法一定正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a829fdd8ec0f3b7ede883cf2c3e53b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c814128ea2139e33db94ea590e7c2223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aec19b68e3add9d5bfcc6269a1855b87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/291c25fc6a69d6d0ccfb8d839b9b4462.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/365b38a7689a8eede6820cd6f1fe952b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee9b42973c53907f09f2de384c42fc5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d20c1e5866f81c045a596079ac4a7671.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e382c9bafdc5d09498b92f5248d01c19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54015ff5b49e3283901da1291b6b921d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46f6872ffb1934339c53c2c2282d5889.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9314bd1d7a6e070f4f2428f9a321804e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f81ee8fc80a880ccceac24aa739fac39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3acd1ce3eb1d1e6db710aeeab22acead.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9076e49b40d78ba58c352d7c8ae0efec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/190396fabedaf4309e8da9d0d3453e05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4de3a6c8f62c09a9be66051dde666c3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3834d7ec7531f3c3c0ce9b286f7a49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a829fdd8ec0f3b7ede883cf2c3e53b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9109c96558079bb0760bebddaa24c29d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
A.若![]() ![]() ![]() ![]() ![]() ![]() ![]() |
B.![]() ![]() |
C.若![]() ![]() ![]() |
D.若![]() ![]() ![]() ![]() ![]() |
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名校
9 . 下面说法中正确的有( )
①在
内任取一实数
,则使
的概率为
;
②“类比平面三角形的性质,推测空间四面体的性质”为演绎推理;
③十进制数78转换成二进制数为
;
④若一组数据
的方差为10,则另一组数据
的方差为11.
①在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f00f2f6ab162f9333ec55db195d663b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc844e4ff25b1255760ed35e04956f9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
②“类比平面三角形的性质,推测空间四面体的性质”为演绎推理;
③十进制数78转换成二进制数为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ade2e47530816f8a8715e09848f9e28c.png)
④若一组数据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fe1c31a81f198c443e71b83ca662939.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cf17ff8d6d8cb4daeade49274a7e5d4.png)
A.②③ | B.②④ | C.①③ | D.①④ |
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2022-06-01更新
|
310次组卷
|
3卷引用:黑龙江省哈尔滨市第三中学校2022届高三第五次高考模拟考试文科数学试题
10 . 赵爽弦图(如图1)中的大正方形是由4个全等的直角三角形和中间的小正方形拼接而成的,若直角三角形的两条直角边长为a,b,斜边长为c,由大正方形面积等于4个直角三角形的面积与中间小正方形的面积之和可得勾股定理
.仿照赵爽弦图构造如图2所示的菱形,它是由两对全等的直角三角形和中间的矩形拼接而成的,设直角三角形的斜边都为1,其中一对直角三角形含有锐角
,另一对直角三角形含有锐角
(位置如图2所示).借鉴勾股定理的推导思路可以得到结论( )
![](https://img.xkw.com/dksih/QBM/2022/4/28/2967738290831360/2969853450657792/STEM/07f9afa0-2073-4adb-b8eb-40cd49cd8f22.png?resizew=348)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3133ef62aad6bdd6637140620f068fad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://img.xkw.com/dksih/QBM/2022/4/28/2967738290831360/2969853450657792/STEM/07f9afa0-2073-4adb-b8eb-40cd49cd8f22.png?resizew=348)
A.![]() | B.![]() |
C.![]() | D.![]() |
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2022-05-01更新
|
1913次组卷
|
6卷引用:广东省2022届高三二模数学试题
广东省2022届高三二模数学试题广东省佛山市南海区桂华中学2022届高三下学期第三次大测数学试题(已下线)专题2 赵爽弦图(已下线)模块二情境7 发现数学之美5.5三角恒等变换(已下线)【第二练】5.5.1课时1 两角和与差的正弦、余弦公式