(完整word版)高考二次函数专题(word文档良心出品).pdf
二次函数一填空题:1 在区间 12,2上,函数f(x)=x2-px+q 与 g(x)=2x+1x2在同一点取得相同的最小值,那么 f(x)在12,2上的最大值是 4 2设函数f(x)=x2+bx+cx02 x0,若 f(-4)=f(0),f(-2)=-2,则关于x 的方程 f(x)=x 的解的个数为 3(-2,-1,2)3函数2(0,)yxbxc x是单调函数的充要条件的是 b0 4对于二次函数22()42(2)21f xxpxpp,若在区间1,1内至少存在一个数c 使得()0f c,则实数p的取值范围是5已知方程2(1)10 xa xab的两根为12x x、,并且1201xx,则ba的取值范围是6若函数f(x)=x2+(a+2)x+3,x a,b 的图象关于直线x=1 对称,则b=7若不等式x4+2x2+a2-a-2 0 对任意实数x恒成立,则实数a 的取值范围是8已知函数f(x)=|x2-2 ax+b|(xR),给出下列命题:f(x)必是偶函数;当f(0)=f(2)时,f(x)的图象必关于直线x=1 对称;若a2-b0,则 f(x)在区间 a,+)上是增函数;f(x)有最大值|a2-b|;其中正确命题的序号是9已知二次函数2()f xaxbxc,满足条件(2)(2)fxfx,其图象的顶点为A,又图象与x轴交于点B、C,其中B 点的坐标为(1,0),ABC的面积S=54,试确定这个二次函数的解析式10 已知ab、为常数,若22()43,()1024f xxxf axbxx,则5ab11 已知函数2()21,f xxx若存在实数t,当1,xm时,()f xtx恒成立,则实数m的最大值为12设()f x是定义在R上的奇函数,且当0 x时,2()f xx,若对任意的2xtt,不等式()2()f xtf x恒成立,则实数t的取值范围是13设2 (|1)()(|1)xxf xxx,()g x是二次函数,若()f g x的值域是0,则()g x的值域是14函数2254()22xxf xxx的最小值为二、解答题:15已知函数2213222fxxmxmm,当(0,)x时,恒有()0f x,求 m 的取值范围16设 a 为实数,函数f(x)=x2+|x-a|+1,xR(1)讨论函数f(x)的奇偶性;(2)求函数f(x)的最小值17已知2()(0)fxaxbxc a的图象过点(-1,0),是否存在常数a,b,c,使得不等式21()2xxf x对一切实数x 都成立文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G718已知a 是实数,函数2()223f xaxxa,如果函数()yf x在区间1,1上有零点,求a的取值范围19设函数f(x)=,22aaxxc其中 a 为实数()若 f(x)的定义域为R,求 a 的取值范围;文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7()当 f(x)的定义域为R时,求 f(x)的单减区间20已知函数2()1f xxx,,是方程 f(x)=0 的两个根(),()fx 是 f(x)的导数;设11a,1()()nnnnf aaafa(n=1,2,)(1)求,的值;(2)(理做)证明:对任意的正整数n,都有na;(3)记lnnnnaba(n=1,2,),求数列 bn 的前 n 项和 Sn1二次函数答案新海高级中学杨绪成舒燕一、填空题:文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G71.在区间 12,2上,函数f(x)=x2-px+q 与 g(x)=2x+1x2在同一点取得相同的最小值,那么 f(x)在12,2上的最大值是 4 2.设函数 f(x)=x2+bx+cx02 x0,若 f(-4)=f(0),f(-2)=-2,则关于x 的方程 f(x)=x 的解的个数为 3 .3.函数2(0,)yxbxc x是单调函数的充要条件的是b0 .4.对于二次函数22()42(2)21f xxpxpp,若在区间1,1内至少存在一个数c 使得()0f c,则实数p的取值范围是 (-3,1.5).5.已知方程2(1)10 xa xab的两根为12x x、,并且1201xx,则ba的取值范围是(,2.6若函数f(x)=x2+(a+2)x+3,x a,b 的图象关于直线x=1 对称,则b=6 .7若不等式x4+2x2+a2-a-2 0 对任意实数x 恒成立,则实数a 的取值范围是(,12,).8已知函数f(x)=|x2-2 ax+b|(xR),给出下列命题:f(x)必是偶函数;当f(0)=f(2)时,f(x)的图象必关于直线x=1对称;若a2-b 0,则 f(x)在区间 a,+)上是增函数;f(x)有最大值|a2-b|;其中正确命题的序号是 .9.已知二次函数2()f xaxbxc,满足条件(2)(2)fxfx,其图象的顶点为A,又图象与x轴交于点B、C,其中 B点的坐标为(1,0),ABC的面积 S=54,试确定这个二次函数的解析式222(2)182(2)18yxyx或.10.已知ab、为常数,若22()43,()1024f xxxf axbxx,则5ab 2 .11.已知函数2()21,f xxx若存在实数t,当1,xm时,()f xtx恒成立,则实数m的最大值为 4 .12.设()f x是定义在R上的奇函数,且当0 x时,2()f xx,若对任意的2xtt,不等式()2()f xtf x恒成立,则实数t的取值范围是2,).13.设2 (|1)()(|1)xxf xxx,()g x是二次函数,若()f g x的值域是0,则()g x的值域是0,);14.函数2254()22xxf xxx的最小值为2 21.二、解答题:15已知函数2213()222f xxmxmm,当(0,)x时,恒有()0f x,求 m 的取值范围思路点拨:此题为动轴定区间问题,需对对称轴进行讨论.解:213()()22fxxmm文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7当0m即0m时,2133(0)00;222fmmm当0m即0m时,130322mm.综上得:3m或32m.点评:分类讨论要做到不漏掉任何情况,尤其是端点处的数值不可忽视.最后结果要取并集.变式训练:已知2()cos3 sincos1()Rf xaxaxxa,当0,2x时,)(xf的最小值为2,求a的值.解:()sin(2)162af xax,512,sin(2)1,66662xx.当0a时,min()12,62af xaa当0a时,min()12,322aaf xa16设 a 为实数,函数f(x)=x2+|x-a|+1,xR,(1)讨论函数f(x)的奇偶性;(2)求函数f(x)的最小值思路点拨:去绝对值,将问题转化成研究分段函数的性质.解:(1)当0a时,2()1f xxx,函数)(xf为偶函数;当0a时,22()1,()21,()()f aafaaaf xfa,此时函数)(xf为非奇非偶函数;(2)1)(2axxxf=222213()()1()24131()()()24xa xaxxaxaxxaxaxa xa当12a时,222minmin3(1)1,(1)4xxaaxxaa,此时,min3()4fxa;当1122a时,2min()1;fxa当12a时,min3().4fxa点评:把握每段函数,同时综观函数整体特点,是解决本题的关键.17.已知2()(0)f xaxbxc a的图象过点(-1,0),是否存在常数a,b,c,使得不等式21()2xxf x对一切实数x 都成立.思路点拨:本题为不等式恒成立时探寻参数的取值问题.解:当1x时,1()1(1)1,1f xfabc,又(1)00fabc可得12bac;由xxf)(对一切实数X都成立,文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7则22001(1)0010216aaaxbxcaxxcac于是,0c又161)2(2caac,161ac,此时41ca.综上可得,存在21,41bca,使得不等式212xxfx对一切实数X都成立.点评:挖掘不等式21()2xxf x中隐含的特殊值,得到1)(1xf以及111616ac是解题关键.变式训练:设函数21()axf xbxc是奇函数(cba,都是整数)且(1)2,(2)3ff.(1)求cba,的值;(2)当)(,0 xfx的单调性如何?用单调性定义证明你的结论.略解(1)0,1 cba.(2)当0,()xf x在(,1上单调递增,在 1,0)上单调递减.18.已知a是实数,函数2()223f xaxxa,如果函数()yf x在区间1,1上有零点,求a的取值范围.解析 1:函数()yf x 在区间-1,1 上有零点,即方程2()223f xaxxa=0 在-1,1 上有解.a=0 时,不符合题意,所以a0,方程 f(x)=0 在-1,1 上有解(1)(1)0ff或(1)0(1)048(3)01 1.1afafaaa15a或372a或5a372a或 a1.所以实数a 的取值范围是372a或 a1.点评:通过数形结合来解决一元二次方程根的分布问题.解析 2:a=0 时,不符合题意,所以a0,又2()223f xaxxa=0在-1,1 上有解,2(21)32xax在-1,1 上有解212132xax在-1,1 上有解,问题转化为求函数22132xyx-1,1 上的值域;设t=3-2x,x-1,1,则 23xt,t 1,5,21(3)217(6)22tyttt,设2277().()tg ttg ttt,1,7)t时,()0g t,此函数 g(t)单调递减,(7,5t时,()g t 0,此函数 g(t)单调递增,y 的取值范围是73,1,2()223f xaxxa=0 在-1,1 上有解1a73,11a或372a.点评:将原题中的方程化成212132xax的形式,问题转化为求函数22132xyx-1,1 上的值域的问题,是解析 2 的思路走向.文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G4 HA10K3A7M3Q4 ZA1U6G5C10G7文档编码:CF4I8E9X7G