初二数学经典难题.doc

2012年初二数学经典难题一、解答题（共10小题，满分100分）1已知：如图，P是正方形ABCD内点，PAD=PDA=15°求证：PBC是正三角形（初二） 2已知：如图，在四边形ABCD中，AD=BC，M、N分别是AB、CD的中点，AD、BC的延长线交MN于E、F求证：DEN=F 3如图，分别以ABC的边AC、BC为一边，在ABC外作正方形ACDE和CBFG，点P是EF的中点，求证：点P到AB的距离是AB的一半 4设P是平行四边形ABCD内部的一点，且PBA=PDA求证：PAB=PCB 5P为正方形ABCD内的一点，并且PA=a，PB=2a，PC=3a，求正方形的边长 6一个圆柱形容器的容积为V立方米，开始用一根小水管向容器内注水，水面高度达到容器高度一半后，改用一根口径为小水管2倍的大水管注水向容器中注满水的全过程共用时间t分求两根水管各自注水的速度 7如图1，已知正比例函数和反比例函数的图象都经过点M（-2，-1），且P（-1，-2）为双曲线上的一点，Q为坐标平面上一动点，PA垂直于x轴，QB垂直于y轴，垂足分别是A、B（1）写出正比例函数和反比例函数的关系式；（2）当点Q在直线MO上运动时，直线MO上是否存在这样的点Q，使得OBQ与OAP面积相等？如果存在，请求出点的坐标，如果不存在，请说明理由；（3）如图2，当点Q在第一象限中的双曲线上运动时，作以OP、OQ为邻边的平行四边形OPCQ，求平行四边形OPCQ周长的最小值8如图，P是边长为1的正方形ABCD对角线AC上一动点（P与A、C不重合），点E在线段BC上，且PE=PB（1）求证：PE=PD；PEPD；（2）设AP=x，PBE的面积为y求出y关于x的函数关系式，并写出x的取值范围；当x取何值时，y取得最大值，并求出这个最大值9如图，直线y=k1x+b与反比例函数yk2x（x0）的图象交于A（1，6），B（a，3）两点（1）求k1、k2的值（2）直接写出k1x+bk2x0时x的取值范围；（3）如图，等腰梯形OBCD中，BCOD，OB=CD，OD边在x轴上，过点C作CEOD于点E，CE和反比例函数的图象交于点P，当梯形OBCD的面积为12时，请判断PC和PE的大小关系，并说明理由 10如图，已知直线y=12待添加的隐藏文字内容1x与双曲线ykx(k0)交于A，B两点，且点A的横坐标为4（1）求k的值；（2）若双曲线ykx(k0)上一点C的纵坐标为8，求AOC的面积；（3）过原点O的另一条直线l交双曲线ykx(k0)于P，Q两点（P点在第一象限），若由点A，B，P，Q为顶点组成的四边形面积为24，求点P的坐标29C91AFE4CED1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFEDD1B6C87D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF95AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9D1B6C8795AD9C91AFE4CED1B6C8795A1AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFC91FE4CED1D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6CD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF8795AD9C91FE4CED1D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C87D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF5D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFAD9C91FE4CED1B6C8795AD29C91AFB6C8795AD29C91AFB6C8795AD29C91AFD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFFE4CED1B6C8795AD29C91AFC8795AD9C91FE4CED1B6C8795AD29C91AFD1B6C8795AD9C91AFED1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8D1B6C8795AD9C91AFE4CED1D91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFC91FE4CED1D1B6C871AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFC91FE4CED1D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6CD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF8795AD9C91FE4CED1D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C87D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF5D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFAD9C91FE4CED1B6C8795AD29C91AFB6C8795AD29C91AFB6C8795AD29C91AFD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8791AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFC91FE4CED1D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6CD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF8795AD9C91FE4CED1D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C87D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF5D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFAD9C91FE4CED1B6C8795AD29C91AFB6C8795AD29C91AFB6C8795AD29C91AFD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFFE4CED1B6C8795AD29C91AFC8795AD9C91FE4CED1B6C8795AD29C91AFD1B6C8795AD9C91AFED1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8D1B6C8795AD9C91AFE4CED15AD9C91D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFFE4CED1B6C8795AD29C91AFC8795AD9C91FE4CED1B6C8795AD29C91AFD1B6C8795AD9C91AFED1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8D1B6C8795AD9C91AFE4CED195AD9C91AFE4CED1B6C8795AD91AFE4CED1B6CD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF8795AD9C91FE4CED1D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C87D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF5D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFAD9C91FE4CED1B6C8795AD29C91AFB6C8795AD29C91AFB6C8795AD29C91AFD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFFE4CED1B6C8795AD29C91AFC8795AD9C91FE4CED1B6C8795AD29C91AFD1B6C8795AD9C91AFED1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF795AD9C91FE4CED1B6C8795ADD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF29C91AF4CED1B6C8795AD1B6C8795AD9C91AFE4CED1B6C8795AD91AFD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFD1B6C8795AD29C91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C9D1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF1AFD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AFD1BD1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF1B6C8795AD9C91AFE4CED1B6C8795AD91AFE4CED1B6C8795AD9C91FE4CED1B6C8795AD29C91AF4CED1B6C8795AD29C91AFE4CED1B6C8795ADC6F554C62