(2)在x轴上找一点D,连接DB,使得△ADB与△ABC相似(不包括全等),并求点D的坐标;
P?DQm?(3)在(2)的条件下,如P,Q分别是AB和AD上的动点,连接PQ,设A,
问是否存在这样的m使得△APQ与△ADB相似,如存在,请求出m的值;如不存在,请说明理由.
y B x
A O C 第24题图
济南市2007年高中阶段学校招生考试
数学试题参考答案及评分标准
一、选择题 1.C 2.D 8.A 9.B 二、填空题 13.x??
3.B 10.C
2
4.B 11.C
45.C 12.B
6.A 7.D
1 214.y(y?2) 15.1.3?10
16.
2 317.(123?36)
三、解答题 18.(1)解:
x2??2 x?33?x去分母得:x?2?2(x?3) ··································································································· 1分 解得:x?4 ··························································································································· 2分 经检验x?4是原方程的根. ································································································· 3分 (2)解法一:①?2?②得5x?10 ··················································································· 4分 解得:x?2 ··························································································································· 5分 将x?2代入①得y??2 ······································································································· 6分
?x?2 ······································································································· 7分 ?方程组的解为??y??2解法二:由①得y?2x?6 ③ ·························································································· 4分 将③代入②得x?2(2x?6)??2
解得:x?2 ··························································································································· 5分 将x?2代入③得y??2 ······································································································· 6分
?方程组的解为??x?2 ······································································································· 7分
?y??219.(1)证明:?AF?BE,EF?EF,?AE?BF ················································· 1分 ?四边形ABCD是矩形,
?∠A?∠B?90?,AD?BC,
O ?△DAE≌△CBF ························································ 2分 ?DE?CF······································································ 3分 C B A (2)解:过点O作OC?AB,垂足为C,
第19题图2
则有AC?BC ·································································· 4分 ?AB?4,?AC?2 ··········································································································· 5分 在Rt△AOC中,
················································································· 6分 OC?OA2?AC2?32?22?5 ·
sinA?OC5 ················································································································· 7分 ?OA320.解:(1)?在7张卡片中共有两张卡片写有数字1 ···················································· 1分
2················································ 2分 ?从中任意抽取一张卡片,卡片上写有数字1的概率是 ·7(2)组成的所有两位数列表为: 十位数 个位数 1 2 3 或列树状图为:
1 2 3 4 十位数
1 1 1 2 3 2 3 2 3 2 3 个位数 1
(11) (12) (13)((( 21) (22) (23) 31) (32) (33) 41) (42) (43)
········································································· 6分
1 11 12 13 2 21 22 23 3 31 32 33 4 41 42 43 ?这个两位数大于22的概率为
7. ···················································································· 8分 1221.解:(1)由租用甲种汽车x辆,则租用乙种汽车(8?x)辆 ········································ 1分
?40x?30(8?x)≥290由题意得:? ····················································································· 4分
10x?20(8?x)≥100?解得:5≤x≤6 ··················································································································· 5分
即共有2种租车方案:
第一种是租用甲种汽车5辆,乙种汽车3辆; 第二种是租用甲种汽车6辆,乙种汽车2辆. ····································································· 6分 (2)第一种租车方案的费用为5?2000?3?1800?15400元; 第二种租车方案的费用为6?2000?2?1800?15600元 ··················································· 7分
······························································································ 8分 ?第一种租车方案更省费用. ·
22.解:(1)过点D作DM?BC,垂足为M,
D 在Rt△DMC中, A DM?CD?sinC?10?4?8 ········································· 1分 5B F
························· 2分 CM?CD2?DM2?102?82?6 ·
?BM?BC?CM?10?6?4,?AD?4 ··············· 3分 第22题图
11?S梯形ABCD?(AD?BC)DM?(4?10)?8?56························································· 4分
22(2)设运动时间为x秒,则有BE?CF?x,EC?10?x ············································ 5分 过点F作FN?BC,垂足为N,
4sinC?x 在Rt△FNC中,FN?CF?············································································· 6分
51142?S△EFC?EC?FN?(10?x)?x??x2?4x ······················································· 7分
2255当x??E M N
C
24?5时,S△EFC???52?4?5?10
5?2?2?????5?即△EFC面积的最大值为10 ······························································································· 8分 此时,点E,F分别在BC,CD的中点处 ·········································································· 9分 23.解:(1)?∠AOC?90,
??AC是?B的直径,?AC?2 ·························································································· 1分
又?点A的坐标为(?3,0),?OA?3 ?OC?AC2?OA2?22?(3)2?1 ············································································ 2分
OC1?,?∠CAO?30? ········································································ 3分 AC2(2)如图,连接OB,过点D作DE?x轴于点E ··························································· 4分 ?OD为?B的切线, ?sin∠CAO??OB?OD,?∠BOD?90? ·························································································· 5分
y ?AB?OB,?∠AOB?∠OAB?30?,
CD A B ?∠AOD?∠AOB?∠BOD?30??90??120?,
在△AOD中,∠ODA?180?120?30?30?∠OAD
????O E 第23题图
x ················································································································· 6分 ?OD?OA?3
在Rt△DOE中,∠DOE?180?120?60
???313sin60?? ,ED?OD??OE?OD?cos60??OD?222?33? ····································································································· 7分 ?点D的坐标为???2,?2??设过D点的反比例函数的表达式为y?k x?k?3333 ············································································································· 8分 ??22433 ····························································································································· 9分 4x?y?0),C(1,0) 24.解:(1)?点A(?3,?AC?4,BC?tan∠BAC?AC?3?4?3,B点坐标为(1,3) ································· 1分 4设过点A,B的直线的函数表达式为y?kx?b,
由??0?k?(?3)?b39 得k?,b? ················································································· 2分
443?k?b?39x? ··············································································· 3分 44y (2)如图1,过点B作BD?AB,交x轴于点D, B 在Rt△ABC和Rt△ADB中,
P ?∠BAC?∠DAB ?Rt△ABC∽R△tAD,B
?D点为所求 ··································································· 4分
4O QC D x A 又tan∠ADB?tan∠ABC?, 3第24题图1
49?CD?BC?tan∠ADB?3??·················································································· 5分
34?直线AB的函数表达式为y??OD?OC?CD?13?13?,?D?,··············································································· 6分 0? ·44??(3)这样的m存在 ················································································································ 7分
在Rt△ABC中,由勾股定理得AB?5 如图1,当PQ∥BD时,△APQ∽△ABD
y P B A Q O C 第24题图2
D x
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