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1.请分别从内容、结构和语言三方面分析本文使用的三节诗句的作用。(6分)

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040](1)解 ①如图1,当在△ABC内时,重叠部分是平行四边形,由题意得:

      解得x=……(2分)

  ②如图3,当在△ABC内时,重叠部分是平行四边形,由题意得:

      N=   列式得(=

解得x=……(2分)

综上所述,当△与△重叠部分面积 为平方厘米时,△移动的时间为或()秒。

图1
 
图2
 
图3
 
图1
 

(2)  ①如图1,当0≤x≤时  ……(1分)

②如图2,当≤x≤时,如图,△DN, △,△是等腰直角三角形, N=,GF=MN=,

…(3分)

③如图3,当≤x≤时,…(1分)

(3)①当0≤x≤时,   ……(1分)

②当≤x≤时,  ……(2分)

③当≤x≤时,  ……(1分)

所以,△与△重叠部分面积的最大值为5。

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039](1) 将点A(-4,8)的坐标代入,解得.    ……1分

将点B(2,n)的坐标代入,求得点B的坐标为(2,2),

则点B关于x轴对称点P的坐标为(2,-2).          ……1分

直线AP的解析式是.                 ……1分

y=0,得.即所求点Q的坐标是(,0).      ……1分

(2)① 解法1:CQ=︱-2-︱=,       ……1分

故将抛物线向左平移个单位时,AC+CB′最短,

此时抛物线的函数解析式为.         ……1分

解法2:设将抛物线向左平移m个单位,则平移后A′,B′的坐标分别为A′(-4-m,8)和B′(2-m,2),点A′关于x轴对称点的坐标为A′′(-4-m,-8).

直线A′′B′的解析式为.  要使AC+CB′最短,点C应在直线A′′B′上,将点C(-2,0)代入直线A′′B′的解析式,解得

故将抛物线向左平移个单位时AC+CB′最短,此时抛物线的函数解析式为.                    ……1分

② 左右平移抛物线,因为线段AB′和CD的长是定值,所以要使四边形ABCD的周长最短,只要使AD+CB′最短;                         ……1分

第一种情况:如果将抛物线向右平移,显然有AD+CB′>AD+CB,因此不存在某个位置,使四边形ABCD的周长最短.……1分

第二种情况:设抛物线向左平移了b个单位,则点A′和点B′的坐标分别为A′(-4-b,8)和B′(2-b,2).

因为CD=2,因此将点B′向左平移2个单位得B′′(-b,2),

要使AD+CB′最短,只要使AD+DB′′最短.    ……1分

A′关于x轴对称点的坐标为A′′(-4-b,-8),直线A′′B′′的解析式为.要使AD+DB′′最短,点D应在直线A′′B′′上,将点D(-4,0)代入直线A′′B′′的解析式,解得.故将抛物线向左平移时,存在某个位置,使四边形ABCD的周长最短,此时抛物线的函数解析式为.……1分

试题详情

038]解:(1)矩形(长方形);

(2)①

,即.································ 4分

同理

.······················································· 6分

②在中,

[来源:ZXXK].··············································· 7分

.设,在中, ,解得.·· 8分

.······················································································· 9分

(3)存在这样的点和点,使.························································· 10分

的坐标是.·························································· 12分

对于第(3)题,我们提供如下详细解答,对学生无此要求.

过点,连结,则

.设

①   如图1,当点P在点B左侧时,

中,

解得(不符实际,舍去).

②如图2,当点P在点B右侧时,

中,,解得

.综上可知,存在点,使

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037]解:(1)设第一象限内的点B(m,n),则tan∠POB,得m=9n,又点B在函数   的图象上,得,所以m=3(-3舍去),点B

AB∥x轴,所以点A(),所以

(2)由条件可知所求抛物线开口向下,设点A(a , a),B(a),则AB=a = ,

所以,解得 .

a = 3时,点A(―3,―3),B(―,―3),因为顶点在y = x上,所以顶点为(-,-),所以可设二次函数为,点A代入,解得k= ,所以所求函数解析式为 .

同理,当a = 时,所求函数解析式为

(3)设A(a , a),B(a),由条件可知抛物线的对称轴为 .

设所求二次函数解析式为: .

A(a , a)代入,解得,所以点P到直线AB的距离为3或

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036]解:(1)由已知,得

.························ (1分)

设过点的抛物线的解析式为.将点的坐标代入,得.[来源:学&将和点的坐标分别代入,得··········································································· (2分)

解这个方程组,[来源:##]故抛物线的解析式为.············ (3分)

(2)成立.························································································· (4分)

在该抛物线上,且它的横坐标为的纵坐标为.··················· (5分)

的解析式为

将点的坐标分别代入,得

  解得

的解析式为.····································· (7分)

过点于点,则

.又

.[来

(3)上,,则设

①若,则

解得,此时点与点重合.

②若,则,解得 ,此时轴.

与该抛物线在第一象限内的交点的横坐标为1,的纵坐标为

③若,则,[来

解得,此时是等腰直角三角形.

过点轴于点,则,设

解得(舍去)..(12分)

综上所述,存在三个满足条件的点,即

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035]解:(1)(1,0)························································································· 1分

 点P运动速度每秒钟1个单位长度.··········································································· 2分

(2) 过点BFy轴于点轴于点,则=8,

  ∴

 在Rt△AFB中,          3分

 过点轴于点,与的延长线交于点

∴△ABF≌△BCH

 

∴所求C点的坐标为(14,12).            4分

(3) 过点PPMy轴于点MPN轴于点N

则△APM∽△ABF

 . 

 ∴.  ∴

设△OPQ的面积为(平方单位)

(0≤≤10) ························································ 5分

说明:未注明自变量的取值范围不扣分.

 ∵<0  ∴当时, △OPQ的面积最大.······························ 6分

 此时P的坐标为() .················································································· 7分

(4)  时,  OPPQ相等.························································· 9分

 对一个加1分,不需写求解过程.

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034]解:(1)2. ……………2分

(2)证明:在上取点,使

连结,再在上截取,连结

为正三角形,

=

为正三角形,=

=

′,

的费马点,

的费马点,且=+.………2分

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033]

(1).……………4分

(2)由题意得点与点′关于轴对称,

′的坐标代入

(不合题意,舍去),.……………2分

轴的距离为3.

直线的解析式为

它与轴的交点为轴的距离为.

.……………2分

(3)当点轴的左侧时,若是平行四边形,则平行且等于

向上平移个单位得到,坐标为,代入抛物线的解析式,

得:

(不舍题意,舍去),.……………2分

当点轴的右侧时,若是平行四边形,则互相平分,

关于原点对称,

点坐标代入抛物线解析式得:

(不合题意,舍去),.……………2分

存在这样的点,能使得以为顶点的四边形是平行四边形.

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032]解:(1)在△ABC中,∵

,解得. ··············································································· 4分

(2)①若AC为斜边,则,即,无解.

②若AB为斜边,则,解得,满足

③若BC为斜边,则,解得,满足

. ····································································································· 9分

(3)在△ABC中,作D

,△ABC的面积为S,则

①若点D在线段AB上,

,即

,即

(). ······························ 11分

时(满足),取最大值,从而S取最大值.······················ 13分

②若点D在线段MA上,

同理可得,

(),

易知此时

综合①②得,△ABC的最大面积为.····································································· 14分

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