1 . 如图,直角梯形ABCD中AD∥BC,∠D=90°.∠A的平分线交DC于E,EF⊥AB于F.已知AD=3.5cm,DC=4cm,BC=6.5cm.那么四边形BCEF的周长是( )
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/25/d1929381-16b0-4ee0-9b78-9e8bb6595b43.png?resizew=110)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/25/d1929381-16b0-4ee0-9b78-9e8bb6595b43.png?resizew=110)
A.10cm | B.11cm | C.11.5cm | D.12cm |
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解题方法
2 . 矩形ABCD中,M、N为边AD上两点,连接BM、CN,MN=BM=CN,∠BMD=120°.
(1)如图1,求证:AM=DN;
(2)如图2,点E、F分别在NC、BC上,∠FME=60°,求证:EF= BF+NE;
(3)如图3,在(2)的条件下,过E作EP∥BC交MF于P,2MN=3BF,EP=7,求CE的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/29/e91c5118-c189-47ac-80db-a2c99ce5177d.png?resizew=621)
(1)如图1,求证:AM=DN;
(2)如图2,点E、F分别在NC、BC上,∠FME=60°,求证:EF= BF+NE;
(3)如图3,在(2)的条件下,过E作EP∥BC交MF于P,2MN=3BF,EP=7,求CE的长.
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3 . 我市在创建全国文明城市检查中,发现一些破旧的公交车候车亭有碍观瞻,现已更换新的公交候车亭(图1),图2所示的是侧面示意图,FG为水平线段,PQ⊥FG,点H为垂足,FG=4m, FH=2.4m, 点P在弧FG上,且弧FG所在的圆的圆心O到FG,PQ的距离之比为5:2,则PH的长约为多少米?
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/15/705f6514-61e3-49b7-8199-78b3ffe70e36.png?resizew=309)
您最近一年使用:0次
2020-11-10更新
|
273次组卷
|
4卷引用:人教版浙江省临海市台州学院附中2019-2020学年九年级上学期期中数学试题
人教版浙江省临海市台州学院附中2019-2020学年九年级上学期期中数学试题(已下线)专题2.14 对称图形——圆章末十大题型总结(拔尖篇)-2023-2024学年九年级数学上册举一反三系列(苏科版)(已下线)专题3.12 圆的基本性质章末八大题型总结(拔尖篇)-2023-2024学年九年级数学上册举一反三系列(浙教版)(已下线)专题24.14 圆章末十大题型总结(拔尖篇)-2023-2024学年九年级数学上册举一反三系列(人教版)
4 . 如图,在矩形
中,
=
,
=
.
、
在对角线
上,且
=
,
、
分别是
、
的中点.
(1)求证:
;
(2)点
是对角线
上的点,
=
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/167d31eb8432b5c0364316e5048c23dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/2020/10/30/2582214521217024/2587329354792960/STEM/0729c1f355a24d369778f2d3e8cb4fab.png?resizew=169)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e83f3e8f914ddac7d019edc146c29d90.png)
(2)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7d6902c8862bd2616be038549f77aff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2ff7caec4fdd8fb54a3ffbff9692414.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
您最近一年使用:0次
名校
5 . 我们定义:如图1,在△ABC中,把AB点绕点A顺时针旋转
得到
.把AC绕点A逆时针旋转
得到
,连接
.当
=180°时,我们称△
是△ABC的“旋补三角形”,△A
边
上的中线AD叫做△ABC的“旋补中线”,点A叫做“旋补中心”.
特例感知:
(1) 在图2,图3中,△A
是△ABC的“旋补三角形”,AD是△ABC的“旋补中线”
① 如图2,当△ABC为等边三角形时,AD与BC的数量关系为AD= BC.
②如图3.当∠BAC=90°,BC=8时,则AD长为
[猜想论证]
(2) 在图1中,当△ABC为任意三角形时,猜想AD与BC的数量关系,并给予证明.
[拓展应用]
(3) 如图4,在四边形ABCD内部恰好存在一点P,使△PDC是△PAB的“能补三角形”,自行补图形,∠C=90°,∠D=150°,BC=12,CD=
,AB=2
.直接写出△PAB的“旋补中线”长是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e36471e4e7749cd8da4bc9b4b3dc85fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59ac8c5700ce2de9a140c4adea742168.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ecbed9cb44cd1f0bad05d3db2ffff18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54f3cbee923ebf5179770f7dbb53b38f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8dc4c63a548b91061528aa11058de75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d59152f6b55e50dffbc6e9cda21fde.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54f3cbee923ebf5179770f7dbb53b38f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54f3cbee923ebf5179770f7dbb53b38f.png)
特例感知:
(1) 在图2,图3中,△A
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54f3cbee923ebf5179770f7dbb53b38f.png)
① 如图2,当△ABC为等边三角形时,AD与BC的数量关系为AD= BC.
②如图3.当∠BAC=90°,BC=8时,则AD长为
[猜想论证]
(2) 在图1中,当△ABC为任意三角形时,猜想AD与BC的数量关系,并给予证明.
[拓展应用]
(3) 如图4,在四边形ABCD内部恰好存在一点P,使△PDC是△PAB的“能补三角形”,自行补图形,∠C=90°,∠D=150°,BC=12,CD=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/985f75c624e091eca4809b1dd94f0530.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9766dfef2a4159f49c7bd349fb36d670.png)
![](https://img.xkw.com/dksih/QBM/2020/10/26/2579559719550976/2580738071461888/STEM/a89e26e3602241828651e14976d57b55.png?resizew=479)
您最近一年使用:0次
解题方法
6 . 如图①,四边形
是一张放在平面中的矩形纸片,
.在
边上取一点
,将纸片沿
翻折,使点
落在
边上的点
处.
![](https://img.xkw.com/dksih/QBM/2020/10/27/2579816516526080/2580587862130688/STEM/71e8eeb7-0ad0-4689-bfcf-1891af4a2c96.png)
(1)
_______,
_________;
(2)求
的长;
(3)如图②,若
上有一动点
(不与
重合)自
点沿
向终点
匀速运动,运动的速度为每秒
个单位长度,设运动的时间为
秒,连结
,设
,
①直接写出
与时间
之间的函数关系式;
②当以点
为顶点的三角形为等腰三角形时,求时间
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3241d7fedd89d85711acd7a2635298af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58279a9901ee08190a169a6be1532852.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/828628c0876b45381c9a0edeb0fec236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://img.xkw.com/dksih/QBM/2020/10/27/2579816516526080/2580587862130688/STEM/71e8eeb7-0ad0-4689-bfcf-1891af4a2c96.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32217457c4e96e2ef155cf15c1b65d97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4f76e37d6e6b182896ccaaa187cfe07.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
(3)如图②,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65436512ecbaefba4ac8123c55094211.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b024cf75910c05e1548081b179e8b79.png)
①直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/595044a7750ab4f84519041979c3d780.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
②当以点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48c791ff5843a539bd35aa2cfbd6888c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
您最近一年使用:0次
7 . 【教材呈现】如图是华师版九年级上册数学教材第103页的部分内容.
已知:如图,在
中,
,
是斜边
上的中线.
![](https://img.xkw.com/dksih/QBM/2020/10/27/2579816516526080/2580587862106112/STEM/78672cf5-9b66-4e1f-a73f-fe30343396c7.png)
求证:
.
证明:延长
至点
,使
,连结
.
【问题解决】补全以上证明过程.
证明:延长
至点
,使
,连接
.
【规律探索】如图,在
中,
于点
于点
;点
是
的中点,连结
,若
,则
_______.
![](https://img.xkw.com/dksih/QBM/2020/10/27/2579816516526080/2580587862106112/STEM/006eb126-06d2-444c-81f0-f2430eb47edf.png)
【结论应用】如图,
分别是
的高线,连结
.
分别是
的中点,则
的长为_______.
已知:如图,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f8f88798ec42a58dccd212586382b23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/2020/10/27/2579816516526080/2580587862106112/STEM/78672cf5-9b66-4e1f-a73f-fe30343396c7.png)
求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c71622531dfa894f21b2da123d020d24.png)
证明:延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0fa1aa5a7a5bb172ed4603f17c8b2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c8ba4da3a6b049f010c91ccb4f328ee.png)
【问题解决】补全以上证明过程.
证明:延长
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0fa1aa5a7a5bb172ed4603f17c8b2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7a6824cd221701c7fe3f8cb4db5d6a9.png)
【规律探索】如图,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e3f5dc11efe60b4fd9a13b1d6b83842.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6934e21988a8accddf82f03e71f3a4e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9506adf67d4563138dfeb21365b1ba22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1295be8e311b0f064b9a4c3f0c4570d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6fdecc899f66d582f609fa88de9aa54.png)
![](https://img.xkw.com/dksih/QBM/2020/10/27/2579816516526080/2580587862106112/STEM/006eb126-06d2-444c-81f0-f2430eb47edf.png)
【结论应用】如图,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0f3ea89fd7abeb103734fccd80c26fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9673cc43a0c2b2711a87b6607364fa4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2b5f27a5179dc6d59d373e92bcf4aac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a1a9e8acb9e2dffeaf5ee062d0fa9c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e72b2e1ff83e95df048745322982451.png)
![](https://img.xkw.com/dksih/QBM/2020/10/27/2579816516526080/2580587862106112/STEM/1c99b48b-72aa-4daa-914b-5fa13d650af0.png)
您最近一年使用:0次
8 . 如图,已知直线
交
于
、
两点,
是
的直径,点
为
上一点,且
平分
,过
作
,垂足为
.
(1)求证:
为
的切线;
(2)若
,
的直径为20,求线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.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/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8e2c17d4d575f9c14180c5648b0d6dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0530f462e5ec1e58c46e1f7644d0cc21.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f3ba8b214034c287276f4966069d95e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/27/4c70366c-dce4-4865-8006-43dec55d2e94.png?resizew=160)
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解题方法
9 . 如图1,矩形ABCD中,AB=3,BC=4,点P是线段AD延长线上的一个动点,连接CP,以CP为一边,在CP的左侧作矩形CPFE.
![](https://img.xkw.com/dksih/QBM/2020/10/15/2571316006338560/2574324351320064/STEM/ea71193f17d745beb1ce39331a574bfb.png?resizew=456)
(1)若DP=
,
①如图1,当矩形CPFE的顶点F恰好落在CD的延长线上,求PF的长;
②如图2,求证:点A一定在矩形CPFE的边CE所在的直线上;
③如图3,连接EP,易知EP中点O在CP的垂直平分线上,设CP的垂直平分线交BC的延长线于点G,连接BO,求5BO+3OG的最小值;
(2)如图4,若所作矩形CPFE始终保持CE=
CP,在BC的延长线上取一点H,使CH=2,连接HF,试探究点P移动过程中,HF是否存在最小值,若存在,请直接写出HF的最小值;若不存在,请说明理由.
![](https://img.xkw.com/dksih/QBM/2020/10/15/2571316006338560/2574324351320064/STEM/ea71193f17d745beb1ce39331a574bfb.png?resizew=456)
(1)若DP=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31da7291140e430a11e2a10cc6cdefbb.png)
①如图1,当矩形CPFE的顶点F恰好落在CD的延长线上,求PF的长;
②如图2,求证:点A一定在矩形CPFE的边CE所在的直线上;
③如图3,连接EP,易知EP中点O在CP的垂直平分线上,设CP的垂直平分线交BC的延长线于点G,连接BO,求5BO+3OG的最小值;
(2)如图4,若所作矩形CPFE始终保持CE=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d599cb4a589f90b0205f24c2e1fa021e.png)
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名校
10 . 已知长方形
,
,
,
为
中点,点
从点
出发,沿着
,
边运动到点
停止,点
的速度为
,运动时间为
.
![](https://img.xkw.com/dksih/QBM/2020/10/15/2571332010614784/2572098051612672/STEM/dba270ff-2fc5-4a18-a8be-ac266801eee6.png)
(1)当点
在
边上运动时,
________(用字母
表示);当点
在
边上运动时,
________(用字母
表示);
(2)当
的面积为
时,则
________;
(3)当
为等腰三角形时,则
________.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc11331a7b2d2619b40ee6d34c3bd620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc34db5860990e51ba31edc8cdd077c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://img.xkw.com/dksih/QBM/2020/10/15/2571332010614784/2572098051612672/STEM/dba270ff-2fc5-4a18-a8be-ac266801eee6.png)
(1)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/524f25e1eedbfe399f7f42db890ab89a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9985eaef9e31b243d5aaf89b71f66075.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/786cd645516dde315a4edb05229446fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8da45c443af7994a26ffa9d8894e7262.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/825116eb345f5505ebc8c1cdb8a1f131.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e16391623f297f18753bb51d8314c616.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/825116eb345f5505ebc8c1cdb8a1f131.png)
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