25.已知.如图1.过点作平行于轴的直线.抛物线上的两点的横坐标分别为1和4.直线交轴于点.过点分别作直线的垂线.垂足分别为点..连接. (1)求点的坐标, (2)求证:, (3)点是抛物线对称轴右侧图象上的一动点.过点作交轴于点.是否存在点使得与相似?若存在.请求出所有符合条件的点的坐标,若不存在.请说明理由. 25.(1)解:方法一.如图1.当时, 当时, ∴·············································································· 1分 ······················································································ 2分 设直线的解析式为··············································· 3分 则 解得 ∴直线的解析式为·············································· 4分 当时, ···························································································································· 5分 方法二:求两点坐标同方法一,如图2,作,,垂足分别为.,交轴于点,则四边形和四边形均为矩形,设························· 3分 ······················································································································· 4分 解得 ························································································································· 5分 (2)证明:方法一:在中. ························································································································ 6分 在中. 由(1)得 ··································································································· 7分 ················································································································ 8分 方法二:由 (1)知 ················································································································· 6分 同理: ······································································································· 7分 同理: 即················································································································ 8分 (3)存在. 解:如图3.作轴.垂足为点··········· 9分 又 ···················································· 10分 设.则 ①当时. ································································································ 11分 解得 ···················································································································· 12分 ②当时. ································································································ 13分 解得 综上.存在点.使得与相似.··································· 14分 查看更多

 

题目列表(包括答案和解析)

09年“十一”期间,中国书香文房,魅力山水画廊-宣城吸引了许多外地游客.“一日游宣城,梦里常回首”!上海的小刚也随爸爸来到宣城游玩,由于仅有一天的时间,小刚不能游览所有风景区.于是爸爸让小刚上午从A、鳄鱼湖;B、敬亭山风景区中任意选择一处游玩;下午从C、太极洞;D.恩龙山庄;E、胡氏宗祠选一处游玩.
(1)请用树状图或列表法说明小刚所有可能选择的方式(用字母表示);
(2)在(1)问的选择方式中,求小刚恰好选中A和D这两处的概率.

查看答案和解析>>

期末考试,英语需要用答题卡,从而英语老师给每位同学都设计了一个准考证号,一共是8位数:
规定前两位数字表示入学年份,第3位数字表示所在的年级,第4-5位数字表示所在的班级,第6~7位数字表示座位号,末位数字用1表示男生,用2表示女生.如:09年入学七年级5班13号的一名男学生的准考证号码为 09705131.那么:12年入学七年级4班23号的一名女学生的准考证号码为
 

查看答案和解析>>

受我国经济刺激政策和全球经济复苏的影响,2009年我国房地产市场开始回暖,下图反映08年7月至09年6月我国70个大城市房价同比增长率变化情况(注:同比增长率是指房价与上一年同时期相比增长的百分比)
(1)看图分析:2008年7月房价比2007年7月的房价;2008年8月的房价比2008年7月的房价;(填“高”、“相等”、“低”、“不能确定”.)
(2)从图上可以看出:同比增长率与月份之间折线图可以“近似”的看成一段抛物线,以2008年7月的坐标为(0,7.0)建立平面直角坐标系.请你根据图中信息求出同比增长率与月份之间“近似”的函数关系式,并据此推算2009年9月同比增长率会达到多少?
(3)若从2008年7月到2008年9月房价持平,求从2009年7月开始到2009年9月房价月平均增长率.(结果精确到0.01,可能用到数据:
521
≈22.83
505
≈22.47

精英家教网

查看答案和解析>>

2、据北京市交通管理局统计,截止09年4月1日,北京市机动车保有量已经超过360万辆,将3600000用科学记数法表示正确的是(  )

查看答案和解析>>

4、09年开春后,普降大雨,以下是3月4日各县(市,区)的降水量分布情况(单位:㎜)这组数据的中位数,众数,极差分别是(  )

查看答案和解析>>


同步练习册答案