1 . 设
,
,正实数数列
满足
,且当
时
.求证: ⑴当
时,
; ⑵
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1465145d6bc8543d5c544dd99613970d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08115d6d9f876dea921a4d32260ff1fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27008dcb6262187804a14cab9302a876.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c10652cbb829968425b5d43b3e19eea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a347b7b06cf3541256a952adfe637750.png)
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2 . 如图,
、
是双曲线
的两个焦点,一条直线与双曲线的右支相切,且分别交两条渐近线于A、B.又设O为坐标原点,求证: (1)
; ⑵
、
、A、B四点在同一个圆上.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/565bc68d208cd5e0c90a32851faf3814.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a05d4d803a85dc1059912895954551b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://img.xkw.com/dksih/QBM/2019/1/28/2128340345315328/2129028866695168/STEM/cd48519e-7460-4653-91b5-2403e14064a5.png)
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3 . 如图,设
的外心、内心分别为
、
,
、
、
内的旁心分别为
、
、
. 证明:
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/fbaf18cb-0a76-496a-b1f8-7795a14bf385.png?resizew=182)
(1)
为锐角三角形;
(2)若
的外心为
,则
、
、
三点共线.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e105760638b22b26ff8bec4354255e4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f1ac49b4139636fb1809fe970b23a87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d1a0fd1ad044a9ecfcba672779bd678.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f904e5f274c559bdba741df035ed3461.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/fbaf18cb-0a76-496a-b1f8-7795a14bf385.png?resizew=182)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b341ab9bd1c7472a4ba15dc4cde452ea.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b341ab9bd1c7472a4ba15dc4cde452ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12fe32dfbd66709875c5b9f79c9496da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12fe32dfbd66709875c5b9f79c9496da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e105760638b22b26ff8bec4354255e4c.png)
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2008高三·天津·竞赛
4 . 已知锐角
的三边
的中点分别为
,在
的延长线上分别取点
.若
,证明:
的外心为
的垂心.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/746ee1515a178948b04f535705c6f738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/927456b0989846a2f1573844bbaa2105.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fda6a104a556dcaab64bb93e73e72315.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89fc107c4b33d6dd648b396156494ea9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/207e5e7d8deb755608c75f88a865f4be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14effb5263b6b8ed7748f05586177a63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
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2011高三·天津·竞赛
5 . 在四面体
中.
面
,
已知
是
上一点,满足
,且
(1)证明:
;
(2)若点
到平面
的距离为
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e56c40061164aae019cafc50d81d5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a45b04cc3e5adaeff6f9e01e29032803.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24ff2ae94edbd6437b10463ab52a4f39.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0ed15020c1c669e06a3a3b1557242e9.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6faa377b82f7c39f03875874b78f922b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aefd06c239145a2b6ae87a955aa51414.png)
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6 . 已知有理数数列![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
满足
,其中,
、
,
、
,且
.
证明:(1)
位有理数;
(2)若
、
不是实数,则
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f3c8148f29fa35589392abe05ceb835.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5a3dcf69a81f8945c6a58d0e1f61d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/461af8f960bc02af4ee7f438cd9936c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c814128ea2139e33db94ea590e7c2223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba2314283c849af7e66dbb1d269e962f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31d900314efb0e4cacb6e5de945b5397.png)
证明:(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/450398974b1561ca801e102e16df6789.png)
(2)若
![](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/ffa3205b1df826d63914dcb55bb3ab43.png)
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2005高三·天津·竞赛
7 . 已知椭圆
,其长轴为
,
是椭圆上不同于点
、
的一个动点,直线
、
分别与同一条准线
交于
、
两点.试证明:以线段
为直径的圆必经过椭圆外的一个定点.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dd54b9df3402ad91e2d34c40efe0c7a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a696a182fff038a86b2bbe8ca099442.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a696a182fff038a86b2bbe8ca099442.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/800c5e266b4ad8462a46970f0a232d52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b104090ea2ac34be58a76a4e0e95cb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/123a6eaa56d0b9bd254c6d1361d9114c.png)
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8 . 电脑每秒钟以相同的概率输出一个数字1或2.将输出的前
个数字之和被3整除的概率记为
.证明:
(1)
;
(2)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ffb021aa7d5a5c2f0691e337caad624.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef12a7e06ce3ab13208e3224f8d55510.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b63b357470eb77cc75843509816bc18.png)
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2012高三·天津·竞赛
9 . 已知双曲线的两个焦点坐标分别为
和
,双曲线的一条切线与
轴交于
,且斜率为2.
(1)求双曲线的方程;
(2)若切线与双曲线的切点为
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/813f9a2814013e2407b5b1c216159359.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16fd15503ee692f8286b0312f7c6f0cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46b9768c2c8d0dbdc451c379fa857c11.png)
(1)求双曲线的方程;
(2)若切线与双曲线的切点为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/524d8d29bd10a0daec1da12dc7684316.png)
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10 . 设a为实数,两条抛物线
与
有四个交点
(1)求a的取值范围;
(2)证明这四个交点共圆,并求该圆圆心的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/263c2df4f4312b38903d48189b3bef53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64d21130714686d23efad3a9ddae43a7.png)
(1)求a的取值范围;
(2)证明这四个交点共圆,并求该圆圆心的坐标.
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