已知,
ABC中,AB=AC,∠BAC=2α°,点D为BC边中点,连接AD,点E为线段AD上一动点,把线段CE绕点E顺时针旋转2α°得到线段EF,连接FG,FD.
(1)如图1,当∠BAC=60°时,请直接写出
的值;
(2)如图2,当∠BAC=90°时,(1)中的结论是否仍然成立?若成立,请给出证明;若不成立,请写出正确的结论,并说明理由;
(3)如图3,当点E在AD上移动时,请直接写出点E运动到什么位置时
的值最小.最小值是多少?(用含α的三角函数表示)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
(1)如图1,当∠BAC=60°时,请直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4d4b4f508b7ab4e842831777d5f68a8.png)
(2)如图2,当∠BAC=90°时,(1)中的结论是否仍然成立?若成立,请给出证明;若不成立,请写出正确的结论,并说明理由;
(3)如图3,当点E在AD上移动时,请直接写出点E运动到什么位置时
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bf01a6b3eea534d9995900a2e4c0ee9.png)
![](https://img.xkw.com/dksih/QBM/2020/9/24/2556908512174080/2559015816839168/STEM/51f9fe92c3ea4440bf75fc9c997faa69.png?resizew=481)
2020·河南·二模 查看更多[2]
更新时间:2020-09-27 21:53:55
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相似题推荐
解答题-作图题
|
较难
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【推荐1】如图,点E是正方形ABCD中CD边上任意一点,AB=4,以点A为中心,把△ADE顺时针旋转90°得到△AD′F
(1)画出旋转后的图形,求证:点C、B、F三点共线;
(2)AG平分∠EAF交BC于点G.
①如图2,连接EF.若BG:CE=5:6,求△AEF的面积;
②如图3,若BM、DN分别为正方形的两个外角角平分线,交AG、AE的延长线于点M、N.当MM∥DC时,直接写出DN的长.
(1)画出旋转后的图形,求证:点C、B、F三点共线;
(2)AG平分∠EAF交BC于点G.
①如图2,连接EF.若BG:CE=5:6,求△AEF的面积;
②如图3,若BM、DN分别为正方形的两个外角角平分线,交AG、AE的延长线于点M、N.当MM∥DC时,直接写出DN的长.
![](https://img.xkw.com/dksih/QBM/2019/1/8/2114277406375936/2115783928758272/STEM/9378b096564246c8926d4aafa0a4ff2a.png?resizew=405)
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解答题-作图题
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【推荐2】如图,在
中,
,点D为平面上一点,连接
,将
绕着点A逆时针旋转
得到线段
,连接
,取
的中点F,取
的中点G,连接
,取
的中点M,连接
.
(2)猜想
的度数(用含α的式子表示),并证明.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21958ecce9a9fcccc2998d2ba7990c78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efc7b22d85ff04a0ac89743f0bea1f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e52a8f07834cbbbe4224962672fbbb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2273ae1ee99cec9c1304323bc9ebf75f.png)
(2)猜想
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aea869b465b92ca404a71fe84467cd35.png)
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解答题-问答题
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名校
【推荐3】在平面直角坐标系
中,若将点P沿x轴折叠得到点
,再将点
绕点R顺时针旋转
得到
,则称点
是点P关于x轴-点R的折旋点.
例如:点
关于x轴-点O的折旋点是点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/13/e7f0b467-86ee-43b0-889b-cfc2edd28d90.png?resizew=590)
(1)如图1,点
.
若点B是点A关于x轴-点
的折旋点,则点B的坐标为___________;
若点
是点A关于x轴-点E的折旋点,则点E的坐标为___________;
(2)如图2,
的半径为2,若
上存在点M,使得点
是点M关于x轴-点
的折旋点,且点
在直线
上,求b的取值范围;
(3)
是y轴上的动点,
的半径为2,若
上存在点N,使得点
是点N关于x轴-点
的折旋点,且点
在直线
上,直接写出t的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ee31829d0d4d5f779a957d7df8058ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c02b54dc6b3e1bb6544f47d4c8743fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cee6765a83140d745a6de4c85d9b6b50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cee6765a83140d745a6de4c85d9b6b50.png)
例如:点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9380191d5128132ab5995d3f048d3539.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d832b7711d9d20cd979a9cc5e133ab3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/13/e7f0b467-86ee-43b0-889b-cfc2edd28d90.png?resizew=590)
(1)如图1,点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71885f023172807ad43f2c9a670aa960.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e1c9ae241fd78126274c65e17990c88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbb393a84f6e69a8a5fd2a66e98937fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c650fe55b7603f106c53ca2423451c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5906670e64f26f540295b585c5cd7b15.png)
(2)如图2,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da895d8bd043625a0839128252130d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fe51e659d7482eef32e571379eef3c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1da895d8bd043625a0839128252130d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07565f10847840e0fb07b05218ad17fa.png)
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10ab730f6358a9fd333ae7f5677185a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/989dc4af481c6133824200942b9e5c8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/989dc4af481c6133824200942b9e5c8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28b1ba4307cfde9b424d468bfcdf6c5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fe51e659d7482eef32e571379eef3c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28b1ba4307cfde9b424d468bfcdf6c5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21d532ce76942846df88c6f66112e50f.png)
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解答题-问答题
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较难
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【推荐1】如图,抛物线
经过点
,
,
为抛物线的顶点.
![](https://img.xkw.com/dksih/QBM/2022/4/15/2958774233972736/2961744068124672/STEM/f3f4812d-7187-4b48-9551-5a2387bd787f.png?resizew=228)
(1)求抛物线的解析式及顶点坐标;
(2)点
关于抛物线
的对称轴的对称点为
点,连接
,
,求tan
的值;
(3)在(2)的条件下,点
是抛物线对称轴上一点,且△
和△
相似,请直接写出点
的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58d88bbd34102b55fa928e8ff83f0d52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76d03fa28c117649b0fdfe17eed7b583.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62855ff21228ecea8e28fd0fbeb814ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://img.xkw.com/dksih/QBM/2022/4/15/2958774233972736/2961744068124672/STEM/f3f4812d-7187-4b48-9551-5a2387bd787f.png?resizew=228)
(1)求抛物线的解析式及顶点坐标;
(2)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58d88bbd34102b55fa928e8ff83f0d52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d29e7c4d6216690152430b09f9cf0c2.png)
(3)在(2)的条件下,点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/838132d6d6d5177def1270bddeee3d39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/500df0e782bb081e608f4bc1d576afcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
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解答题-问答题
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【推荐2】如图①,已知抛物线y=﹣
x2+
x+2
与x轴交于A、B两点,与y轴交于C点,抛物线的顶点为Q,连接BC.
![](https://img.xkw.com/dksih/QBM/2019/4/3/2174409352544256/2179408216719360/STEM/6a0bc3d06b1e4a27820914745ff388b8.png?resizew=480)
(1)求直线BC的解析式;
(2)点P是直线BC上方抛物线上的一点,过点P作PD⊥BC于点D,在直线BC上有一动点M,当线段PD最大时,求PM+
MB最小值;
(3)如图②,直线AQ交y轴于G,取线段BC的中点K,连接OK,将△GOK沿直线AQ平移得△G′O'K′,将抛物线y=﹣
x2+
x+2
沿直线AQ平移,记平移后的抛物线为y′,当抛物线y′经过点Q时,记顶点为Q′,是否存在以G'、K'、Q'为顶点的三角形是等腰三角形?若存在,求出点G′的坐标;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7116071164cdc45f5d312a437c68bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://img.xkw.com/dksih/QBM/2019/4/3/2174409352544256/2179408216719360/STEM/6a0bc3d06b1e4a27820914745ff388b8.png?resizew=480)
(1)求直线BC的解析式;
(2)点P是直线BC上方抛物线上的一点,过点P作PD⊥BC于点D,在直线BC上有一动点M,当线段PD最大时,求PM+
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
(3)如图②,直线AQ交y轴于G,取线段BC的中点K,连接OK,将△GOK沿直线AQ平移得△G′O'K′,将抛物线y=﹣
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7116071164cdc45f5d312a437c68bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
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解答题-证明题
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【推荐1】如图,点C是以为直径的
上一点,点D是
的延长线上一点,在
上取一点F,过点F作
的垂线交
于点G,交
的延长线于点E,且
.
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d97cdc586744d208b6f69c9813af977.png)
(2)若点F是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/714cc3707bba3bfdb56e251999be8592.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23df0054320ca1db336635de1ef059f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9171484a68c84cad91e4f2233392f600.png)
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解答题-作图题
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较难
(0.4)
解题方法
【推荐2】如图,在等边
中,点
为
的中点,点
为
上一点,连
、
,将线段
绕点
顺时针旋转至
,使点
落在
的延长线上.
![](https://img.xkw.com/dksih/QBM/2020/12/14/2614182375809024/2614910589722624/STEM/837e3209-a0ae-4306-aca5-87386ad325d3.png)
(1)在图1中画出图形:
①求
的度数;
②探究线段
,
,
之间的数量关系,并加以证明;
(2)如图2,若
,点
为
的中点,连
,将
绕点
顺时针旋转得到
,直线
、
交于点
,连
,在
旋转一周过程中,请直接写出
的面积最大值为__________.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccaee8f228ff24e7c89879bb5b999cf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fc56c77464a17a1e97b568762a3e2c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccaee8f228ff24e7c89879bb5b999cf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://img.xkw.com/dksih/QBM/2020/12/14/2614182375809024/2614910589722624/STEM/837e3209-a0ae-4306-aca5-87386ad325d3.png)
(1)在图1中画出图形:
①求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adcae9d00980803e5955228d1e217abe.png)
②探究线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
(2)如图2,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](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/1e72b2e1ff83e95df048745322982451.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcaecf08a22124a457128fb04c9c02bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12225a1a1eda07908309f8100cc34726.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f50b3ae183997b707d16eb4e7f6712fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcaecf08a22124a457128fb04c9c02bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/357265c532428e886a643e8e653eec9e.png)
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