23.如图9.在平面直角坐标系中.以点为圆心.2为半径作圆.交轴于两点.开口向下的抛物线经过点.且其顶点在上. (1)求的大小, (2)写出两点的坐标, (3)试确定此抛物线的解析式, (4)在该抛物线上是否存在一点.使线段与互相平分?若存在.求出点的坐标,若不存在.请说明理由. (08新疆乌鲁木齐23题解答)23.解:(1)作轴.为垂足. .半径······················································ 1分 .······································ 3分 (2).半径 .故.············································ 5分 ········································································· 6分 (3)由圆与抛物线的对称性可知抛物线的顶点的坐标为··································· 7分 设抛物线解析式·················································································· 8分 把点代入上式.解得······································································· 9分 ····································································································· 10分 (4)假设存在点使线段与互相平分.则四边形是平行四边形········· 11分 且. 轴.点在轴上.·············································································· 12分 又..即. 又满足. 点在抛物线上······································································································ 13分 所以存在使线段与互相平分.···························································· 14分 查看更多

 

题目列表(包括答案和解析)

如图,在平面直角坐标系中,一底角为60°的等腰梯形ABCD的下底AB在x轴的正半轴上,A为坐标原点,点B的坐标为(m,0),对角线BD平分∠ABC,一动点P在BD上以每秒一个单位长度的速度由B→D运动(点P不与B,D重合).过P作PE⊥BD交AB于精英家教网点E,交线段BC(或CD)于点F.
(1)用含m的代数式表示线段AD的长是
 

(2)当直线PE经过点C时,它的解析式为y=
3
x-2
3
,求m的值;
(3)在上述结论下,设动点P运动了t秒时,△AEF的面积为S,求S与t的函数关系式;并写出t为何值时,S取得最大值,最大值是多少?

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如图,在平面直角坐标系中,以点M(0,
3
)为圆心,以2
3
长为半径作⊙M交x轴精英家教网于A,B两点,交y轴于C,D两点,连接AM并延长交⊙M于P点,连接PC交x轴于E.
(1)求出CP所在直线的解析式;
(2)连接AC,请求△ACP的面积.

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如图,在平面直角坐标系中,A(2
3
,0),B(2
3
,2).把矩形OABC逆时针旋转30°得到矩形OA1B1C1
(1)求B1点的坐标;
(2)求过点(2,0)且平分矩形OA1B1C1面积的直线l方程;
(3)设(2)中直线l交y轴于点P,直接写出△PC1O与△PB1A1的面积和的值及△POA1与△PB1C1的面积差的值.
精英家教网

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如图,在平面直角坐标系中,A(8,0)、B(6,2
3
)、C(0,2
3
),有两点P、Q同时从A点出发分别作匀速运动,其中点P沿AB、BC向终点C运动,速度为每精英家教网秒2个单位,点Q沿AD向终点D运动,速度为每秒1个单位,当这两个点中有一个点到达自己的终点时,另一个点也停止运动,设这两点从A点出发运动了t秒.
(1)动点P与Q哪一点先到达自己的终点?此时t为何值?
(2)若⊙B的半径为1,t为何值时以PQ为半径的⊙P既与⊙B相切又与AD相切?
(3)以PQ为直径的圆能否与CD相切?若有可能求出t的值或t的取值范围,若不可能请说明理由.

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如图,在平面直角坐标系中,等腰梯形AOBC的四个顶点坐标分别为A(2,2
3
),O(0,0),B(8精英家教网,0),C(6,2
3
).
(1)求等腰梯形AOBC的面积;
(2)试说明点A在以OB的中点D为圆心,OB为直径的圆上;
(3)在第一象限内确定点M,使△MOB与△AOB相似,求出所有符合条件的点M的坐标.

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