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【330309】2020年湖北省天门、仙桃、潜江、江汉油田中考数学试题

时间:2025-02-09 10:50:28 作者: 字数:25393字

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 天门仙桃潜江江汉油田2020年初中学业水平考试(中考)数学试卷

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一、选择题(本大题共10个小题,在下列各小题中,均给出四个答案,其中有且只有一个正确答案,请将正确答案的字母代号在答题卡上涂黑,涂错或不涂均为零分.)

1.下列各数中,比 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 小的数是(

A. 0 B.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> C.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> D.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】B

【解析】

【分析】

根据有理数的大小比较法则比较即可.

【详解】解: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 小的数是 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

故选:B

【点睛】本题考查了有理数的比较大小,注意绝对值越大的负数的值越小是解题的关键.

2.如图是由4个相同的小正方体组成的立体图形,它的俯视图为(

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

A.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> B.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> C.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> D.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】C

【解析】

【分析】

根据俯视图是从立体图形上方看得到的图形解答即可.

【详解】解:这个由4个相同的小正方体组成的立体图形:从上方可以看到前后两排正方形,后排有两个正方形,前排左边有一个正方形,即C选项符合.

故答案为C

【点睛】本题考查了三规图的知识以及细心观察事物的能力,掌握俯视图的概念和较好的空间想象能力是解答本题的关键.

3.我国自主研发的“北斗系统”现已广泛应用于国防、生产和生活等各个领域,多项技术处于国际领先地位,其星载原子钟的精度,已经提升到了每3000000年误差1秒.数3000000用科学记数法表示为(

A.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> B.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> C.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> D.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】C

【解析】

【分析】

根据科学记数法的定义即可得.

【详解】科学记数法:将一个数表示成 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的形式,其中 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> n为整数,这种记数的方法叫做科学记数法

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

故选:C

【点睛】本题考查了科学记数法的定义,熟记定义是解题关键.

4.将一副三角尺如图摆放,点E <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上,点D <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的延长线上, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,则 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的度数是(

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

A. 15° B. 20° C. 25° D. 30°

【答案】A

【解析】

【分析】

根据三角板的特点可知∠ACB=45°、∠DEF=30°,根据 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 可知∠CEF=∠ACB=45°,最后运用角的和差即可解答.

【详解】解:由三角板的特点可知∠ACB=45°、∠DEF=30°

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

∴∠CEF=∠ACB=45°

∴∠CED=∠CEF-∠DEF=45°-30°=15°

故答案为A

【点睛】本题考查了三角板的特点、平行线的性质以及角的和差,其中掌握平行线的性质是解答本题的关键.

5.下列说法正确的是(

A. 为了解人造卫星的设备零件的质量情况,选择抽样调查

B. 方差是刻画数据波动程度的量

C. 购买一张体育彩票必中奖,是不可能事件

D. 掷一枚质地均匀的硬币,正面朝上的概率为1

【答案】B

【解析】

【分析】

根据抽样调查和普查、方差的意义、随机事件等知识逐项排除即可.

【详解】解:A. 为了解人造卫星的设备零件的质量情况,选择普查,故A选项不符合题意;

B. 方差是刻画数据波动程度的量,故B选项符合题意;

C. 购买一张体育彩票必中奖,是随机事件,故C选项不符合题意;

D. 掷一枚质地均匀的硬币,正面朝上的概率为0.5, D选项不符合题意.

故答案为B

【点睛】本题考查了抽样调查和普查、方差的意义、随机事件等知识,掌握相关基础知识是解答本题的关键.

6.下列运算正确的是(

A.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> B.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> C.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> D.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】D

【解析】

【分析】

根据算术平方根,负整数指数幂,幂的乘方和合并同类项的运算法则进行判断即可.

【详解】A <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,故本选项错误;

B <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,故本选项错误;

C <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,故本选项错误;

D <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,故本选项正确;

故选:D

【点睛】本题考查了算术平方根,负整数指数幂,幂的乘方和合并同类项的运算法则,掌握运算法则是解题关键.

7.对于一次函数 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,下列说法不正确的是(

A <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 图象经过点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> B. 图象与x轴交于点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

C. 图象不经过第四象限 D.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 时, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】D

【解析】

【分析】

根据一次函数的图像与性质即可求解.

【详解】A.图象经过点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,正确;

B.图象与x轴交于点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,正确

C.图象经过第一、二、三象限,故错误;

D. <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 时,y4,故错误;

故选D

【点睛】此题主要考查一次函数的图像与性质,解题的关键是熟知一次函数的性质特点.

8.一个圆锥的底面半径是 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,其侧面展开图的圆心角是120°,则圆锥的母线长是(

A.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> B.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> C.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> D.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】B

【解析】

【分析】

根据题意求出圆锥的底面周长,根据弧长公式计算即可.

【详解】解:圆锥的底面周长=2×π×4

侧面展开图的弧长为

则圆锥母线长= <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 12cm),

故选:B

【点睛】本题考查的是圆锥的计算,正确理解圆锥的侧面展开图与原来的扇形之间的关系是解决本题的关键,理解圆锥的母线长是扇形的半径,圆锥的底面圆周长是扇形的弧长.

9.关于x的方程 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 有两个实数根 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,且 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,那么m的值为(

A.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> B.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> C.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 1 D.  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 4

【答案】A

【解析】

【分析】

通过根与系数之间的关系得到 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,由 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 可求出m的值,通过方程有实数根可得到 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,从而得到m的取值范围,确定m的值.

【详解】解:∵方程 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 有两个实数根 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

整理得, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

解得, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

若使 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 有实数根,则 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

解得, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

所以 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

故选:A

【点睛】本题考查了一元二次方程根与系数之间的关系和跟的判别式,注意使一元二次方程有实数根的条件是解题的关键.

10.如图,已知 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 都是等腰三角形, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 交于点F,连接 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,下列结论:① <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;② <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;③ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 平分 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;④ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> .其中正确结论的个数有(

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

A. 1 B. 2 C. 3 D. 4

【答案】C

【解析】

【分析】

证明△BAD≌△CAE,再利用全等三角形的性质即可判断;②由△BAD≌△CAE可得∠ABF=∠ACF,再由∠ABF+∠BGA=90°、∠BGA=∠CGF证得∠BFC=90°即可判定;③分别过AAM⊥BDAN⊥CE,根据全等三角形面积相等和BD=CE,证得AM=AN,AF平分∠BFE,即可判定;④由AF平分∠BFE结合 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 即可判定.

【详解】解:∵∠BAC=∠EAD

∴∠BAC+∠CAD=∠EAD+∠CAD,即∠BAD=∠CAE

在△BAD和△CAE

AB=AC, ∠BAD=∠CAE,AD=AE

∴△BAD≌△CAE

BD=CE

故①正确;

∵△BAD≌△CAE

∴∠ABF=∠ACF

∵∠ABF+∠BGA=90°、∠BGA=∠CGF

∴∠ACF+∠BGA=90°,

∴∠BFC=90°

故②正确;

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

分别过AAM⊥BDAN⊥CE垂足分别为MN

∵△BAD≌△CAE

S△BAD=S△CAE,

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

BD=CE

AM=AN

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 平分∠BFE,无法证明AF平分∠CAD

故③错误;

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 平分∠BFE <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

故④正确.

故答案为C

【点睛】本题考查了全等三角形的判定与性质、角平分线的判定与性质以及角的和差等知识,其中正确应用角平分线定理是解答本题的关键.

二、填空题(本大题共6个小题,请将结果直接填写在答题卡对应的横线上)

11.n边形的一个内角等于135°,则边数n的值为_________

【答案】8

【解析】

【分析】

先根据多边形的外角与相邻的内角互补求出外角的度数,再根据外角和求边数即可.

【详解】多边形的外角是:180﹣135=45°

n= <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> =8

【点睛】本题考查了多边形的外角和,熟练掌握多边形的外角和等于360°是解答本题的关键.

12.篮球联赛中,每玚比赛都要分出胜负,每队胜1场得2分,负1场得1分.某队14场比赛得到23分,则该队胜了_________场.

【答案】9

【解析】

【分析】

设该对胜x场,则负14-x场,然后根据题意列一元一次方程解答即可.

【详解】解:设该对胜x

由题意得:2x+14-x=23,解得x=9

故答案为9

【点睛】本题考查了一元一次方程的应用,弄清题意、设出未知数、找准等量关系、列出方程是解答本题的关键.

13.如图,海中有个小岛A,一艘轮船由西向东航行,在点B处测得小岛A位于它的东北方向,此时轮船与小岛相距20海里,继续航行至点D处,测得小岛A在它的北偏西60°方向,此时轮船与小岛的距离 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ________海里.

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】20 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【解析】

【分析】

过点AAC⊥BD,根据方位角及三角函数即可求解.

【详解】如图,过点AAC⊥BD

依题意可得∠ABC=45°

∴△ABC是等腰直角三角形,AB=20(海里)

AC=BC=ABsin45°=10 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (海里)

Rt△ACD中,∠ADC=90°-60°=30°

AD=2AC=20 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (海里)

故答案为:20 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【点睛】此题主要考查解直角三角形,解题的关键是熟知特殊角的三角函数值.

14.3张看上去无差别的卡片,上面分别写着234.随机抽取1张后,放回并混在一起,再随机抽取1张,则两次取出的数字之和是奇数的概率为_________

【答案】 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【解析】

【分析】

根据题意列出表格,找出所有可能结果和满足条件的结果即可求出.

【详解】依题意列的表格如下:

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

由表格看出共有9种结果,奇数的结果是4种.

故答案是 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【点睛】本次主要考查了概率知识点,准确的找出所有结果和满足条件的结果是解题关键.

15.某商店销售一批头盔,售价为每顶80元,每月可售出200顶.在“创建文明城市”期间,计划将头盔降价销售,经调查发现:每降价1元,每月可多售出20顶.已知头盔的进价为每顶50元,则该商店每月获得最大利润时,每顶头盔的售价为_______元.

【答案】70

【解析】

【分析】

设降价x元,利润为W,根据题意得出方程,然后求出取最大值时的x值即可得到售价.

【详解】解:设降价x元,利润为W

由题意得:W=(80-50-x)(200+20x)

整理得:W=-20x2+400x+6000=-20(x-10)2+8000

x=10时,可获得最大利润,

此时每顶头盔的售价为:80-10=70(元),

故答案为:70

【点睛】本题考查了二次函数的实际应用,根据题意列出式子是解题关键.

16.如图,已知直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 和点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,过点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> y轴的平行线交直线a于点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,过点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> x轴的平行线交直线b于点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,过点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> y轴的平行线交直线a于点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,过点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> x轴的平行线交直线b于点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,…,按此作法进行下去,则点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的横坐标为____

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【解析】

【分析】

根据题意求出P1,P5,P9的坐标,发现规律即可求解.

【详解】∵ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 在直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 1,1);

过点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> x轴的平行线交直线b于点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 在直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> -2,1

同理求出P3-2-2),P44-2),P544),P6-84),P7-8-8),P816-8),P91616)…

可得P4n+1(22n, 22n )(n≥1n为整数)

4n+1=2021

解得n=505

P2021( <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> , <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> )

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的横坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【点睛】此题主要考查坐标的规律探索,解题的关键是熟知一次函数的图像与性质,找到坐标规律进行求解.

三、解答题(本大题共8个小题)

17.1)先化简,再求值: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,其中 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

2)解不等式组 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,并把它的解集在数轴上表示出来.

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【答案】1 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 2;(2 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,数轴见解析

【解析】

【分析】

1)首先把分式的分子和分母分解因式,把除法去处转化成乘法运算,再把 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 代入计算即可;

2)分别求出不等式组中两不等式的解集,找出解集的公共部分即可.

【详解】(1 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 时,

原式 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

2)解:由 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 得: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 得: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

不等式组的解集为: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

在数轴上表示如下:

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【点睛】本题考查了解一元一次不等式组以及分式 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 化简求值,正确对分式进行通分、约分是关键.

18.在平行四边形 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 中,E <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的中点,请仅用无刻度的直尺完成下列画图,不写画法,保留画图痕迹.

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

1)如图1,在 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上找出一点M,使点M <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的中点;

2)如图2,在 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上找出一点N,使点N <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的一个三等分点.

【答案】1)见解析;(2)见解析

【解析】

【分析】

1)连接对角线AC,BD,再连接E与对角线的交点,与BC的交点即为M点;

2)连接CEBD即为N点,根据相似三角形的性质可得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,于是DN= <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> BD

【详解】解:(1)如图1,点M即为所求;

2)如图2,点N即为所求.

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【点睛】此题主要考查平行四边形与相似三角形的性质,解题的关键是熟知平行四边形的特点.

19.520日九年级复学啦!为了解学生的体温情况,班主任张老师根据全班学生某天上午的《体温监测记载表》,绘制了如下不完整的频数分布表和扇形统计图.

学生体温频数分布表:

组别

温度(℃)

频数(人数)

36.3

6

36.4

a

36.5

20

36.6

4



 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

请根据以上信息,解答下列问题:

1)频数分布表中 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> __________,该班学生体温的众数是_______,中位数是_________

2)扇形统计图中 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> __________,丁组对应的扇形的圆心角是_________度;

3)求该班学生的平均体温(结果保留小数点后一位).

【答案】11036.536.5;(21536;(336.5℃

【解析】

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 分析】

1)先求出调查的学生总人数,再分别减去各组人数即可求出a,再根据众数、中位数的定义即可求解;

2)分别求出甲、丁的占比即可求解;

3)根据加权平均数的定义即可求解.

【详解】解:(1)调查的学生总人数为20÷50%=40(人)

频数分布表中 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

该班学生体温的众数是36.5

中位数是36.5

故答案为: 1036.536.5

2)扇形统计图中 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

丁组对应的扇形的圆心角是 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> =36度;

故答案为:1536

3)该班学生的平均体温为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (℃).

【点睛】此题主要考查统计调查的应用,解题的关键是熟知求出调查的学生总人数.

20.把抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 先向右平移4个单位长度,再向下平移5个单位长度得到抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

1)直接写出抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的函数关系式;

2)动点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 能否在拋物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上?请说明理由;

3)若点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 都在抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上,且 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,比较 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的大小,并说明理由.

【答案】1 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;(2)不在,见解析;(3 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,见解析

【解析】

【分析】

1)先求出抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的顶点坐标,再根据向右平移横坐标加,向下平移纵坐标减求出平移后的抛物线的顶点坐标即可;

2)根据抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的顶点的纵坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,即可判断点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 不在拋物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上;

3)根据抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的增减性质即可解答.

【详解】(1)抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的顶点坐标为(-12)

根据题意,抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的顶点坐标为(-1+42-5),即(3-3)

抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的函数关系式为: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

2)动点P不在抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上.

理由如下:

抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的顶点为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,开口向上,

抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的最低点的纵坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

动点P不在抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上;

3 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

理由如下:

由(1)知抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的对称轴是 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,且开口向上,

在对称轴左侧yx的增大而减小.

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 都在抛物线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上,且 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【点睛】本题考查了二次函数图象与几何变换,二次函数图象上点的坐标特征,熟练掌握平移的规律“左加右减,上加下减”以及熟练掌握二次函数的性质是解题的关键.

21.如图,在 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 中, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,以 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 为直径的⊙O <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 于点D,过点D的直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 于点F,交 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的延长线于点E,且 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

1)求证: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 是⊙O的切线;

2)当 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 时,求 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的长.

【答案】1)见解析;(210

【解析】

【分析】

1)连接 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,由 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 是直径可得到 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,然后通过题中角的关系可推出 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,即可得证;

2)通过 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,得到 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,然后设 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,列分式方程即可解得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,从而得到 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的长.

【详解】(1)证明:如图,连接 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 是直径,

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,即 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的半径,

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的切线.

2)解:∵ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,∵ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

解得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

经检验 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 是所列分式方程的解.

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【分析】本题考查了切线的判定,相似三角形的判定和性质,熟练掌握切线的判定方法是解题的关键.

22.如图,直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 与反比例函数 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的图象交于AB两点,已知点A的坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的面积为8

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

1)填空:反比例函数的关系式为_________________

2)求直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的函数关系式;

3)动点Py轴上运动,当线段 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 之差最大时,求点P的坐标.

【答案】1 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;(2 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;(3 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【解析】

【分析】

1)把点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 代入解析式,即可得到结果;

2)过点A <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 轴于点C,过点B <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 轴于点D <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 交于点E,则四边形 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 为矩形,设点B的坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,表示出△ABE的面积,根据△AOB得面积可得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,得到点B的坐标,代入即可的到解析式;

3)根据“三角形两边之差小于第三边”可知,当点P为直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> y轴的交点时, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 有最大值为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,代入即可求值.

【详解】解:(1)把点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 代入 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 可得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

反比例函数的解析式为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

2)如图,过点A <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 轴于点C,过点B <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 轴于点D <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 交于点E,则四边形 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 为矩形.

设点B的坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,∴ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

A的坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

AB两点均在双曲线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上,

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的面积为8

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,整理得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> .解得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (舍去).

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> .∴点B的坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

设直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的函数关系式为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> .解得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的函数关系式为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

3)如上图,根据“三角形两边之差小于第三边”可知,

当点P为直线 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> y轴的交点时, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 有最大值为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 代入 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

P的坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【点睛】本题主要考查了反比例函数与一次函数的综合,准确分析题意是解题的关键.

23.实践操作:第一步:如图1,将矩形纸片 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 沿过点D的直线折叠,使点A落在 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上的点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 处,得到折痕 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,然后把纸片展平.第二步:如图2,将图1中的矩形纸片 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 沿过点E的直线折叠,点C恰好落在 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上的点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 处,点B落在点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 处,得到折痕 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 于点M <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 于点N,再把纸片展平.

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

问题解决:

1)如图1,填空:四边形 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的形状是_____________________

2)如图2,线段 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 是否相等?若相等,请给出证明;若不等,请说明理由;

3)如图2,若 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,求 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的值.

【答案】1)正方形;(2 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,见解析;(3 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【解析】

【分析】

1)有一组邻边相等且一个角为直角的平行四边形是正方形;

2)连接 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,由(1)问的结论可知, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,又因为矩形纸片 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 沿过点E的直线折叠,可知折叠前后对应角以及对应边相等,有 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,可以证明 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 全等,得到 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,从而有 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

3)由 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,有 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;由折叠知, <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,可以计算出 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;用勾股定理计算出DF的长度,再证明 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 得出等量关系,从而得到 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的值.

【详解】(1)解:∵ABCD是平行四边形,

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

四边形 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 是平行四边形

矩形纸片 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 沿过点D的直线折叠,使点A落在 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 上的点 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

四边形 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的形状是正方形

故最后答案为:四边形 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 的形状是正方形;

2 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

理由如下:如图,连接 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,由(1)知: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

四边形 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 是矩形,

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

由折叠知: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

3)∵ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,∴ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

由折叠知: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,∴ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,则 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 中,由勾股定理得: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

解得: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,即 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

如图,延长 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 交于点G,则 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,∴ <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

【点睛】(1)本问主要考查了正方形的定义,即有一组邻边相等且一个角为直角的平行四边形是正方形,其中明确折叠前后对应边、对应角相等是解题的关键;

2)本问利用了正方形的性质以及折叠前后对应边、对应角相等来证明三角形全等,再根据角相等则边相等即可做题,其中知道角相等则边相等的思想是解题的关键;

3)本问考查了全等三角形、相似三角形的性质、角相等则正切值相等以及勾股定理的应用,其中知道三角形相似则对应边成比例是解题的关键.

24.小华端午节从家里出发,沿笔直道路匀速步行去妈妈经营的商店帮忙,妈妈同时骑三轮车从商店出发,沿相同路线匀速回家装载货物,然后按原路原速返回商店,小华到达商店比妈妈返回商店早5分钟.在此过程中,设妈妈从商店出发开始所用时间为t(分钟),图1表示两人之间的距离s(米)与时间t(分钟)的函数关系的图象;图2中线段 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 表示小华和商店的距离 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (米)与时间t(分钟)的函数关系的图象的一部分,请根据所给信息解答下列问题:

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

1)填空:妈妈骑车的速度是___________/分钟,妈妈在家装载货物所用时间是__________分钟,点M的坐标是___________

2)直接写出妈妈和商店的距离 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (米)与时间t(分钟)的函数关系式,并在图2中画出其函数图象;

3)求t为何值时,两人相距360米.

【答案】11205 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ;(2 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,见解析;(3)当t81232(分钟)时,两人相距360米.

【解析】

【分析】

1)先求出小华步行的速度,然后即可求出妈妈骑车的速度;先求出妈妈回家用的时间,然后根据小华到达商店比妈妈返回商店早5分钟,即可求出装货时间;根据题意和图像可得妈妈在M点时开始返回商店,然后即可求出M的坐标;

2)分①当0≤t15时,②当15≤t20时,③当20≤t≤35时三段求出解析式即可,根据解析式画图即可;

3)由题意知,小华速度为60/分钟,妈妈速度为120/分钟,分①相遇前,②相遇后,③在小华到达以后三种情况讨论即可.

【详解】解:(1)由题意可得:小华步行的速度为: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> =60(米/分钟),

妈妈骑车的速度为: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> =120(米/分钟);

妈妈回家用的时间为: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> =15(分钟),

小华到达商店比妈妈返回商店早5分钟,

可知妈妈在35分钟时返回商店,

装货时间为:35-15×2=5(分钟),

即妈妈在家装载货物的时间为5分钟;

由题意和图像可得妈妈在M点时开始返回商店,

M点的横坐标为:15+5=20(分钟),

此时纵坐标为:20×60=1200(米),

M的坐标为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

故答案为:1205 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

2)①当0≤t15y2=120t

15≤t20y2=1800

20≤t≤35时,设此段函数解析式为y2=kx+b

将(201800),(350),代入得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

解得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

此段的解析式为y2=-120x+4200

综上: <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

其函数图象如图,

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>

3)由题意知,小华速度为60/分钟,妈妈速度为120/分钟,

相遇前,依题意有 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,解得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (分钟);

相遇后,依题意有 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,解得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (分钟);

依题意,当 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 分钟时,妈妈从家里出发开始追赶小华,

此时小华距商店 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a>  <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (米),只需10分钟,

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> 分钟时,小华到达商店,

而此时妈妈距离商店为 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (米) <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (米),

 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> ,解得 <a href="/tags/51/" title="试题" class="c1" target="_blank">试题</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/557/" title="湖北" class="c1" target="_blank">湖北</a> <a href="/tags/975/" title="湖北省" class="c1" target="_blank">湖北省</a> <a href="/tags/1027/" title="仙桃" class="c1" target="_blank">仙桃</a> <a href="/tags/1028/" title="天门" class="c1" target="_blank">天门</a> (分钟),

t81232(分钟)时,两人相距360米.

【点睛】本题考查了一次函数的实际应用,由图像获取正确的信息是解题关键.