һѡ
1.()ʽ(a-2)x2+2(a-2)x-4<0һxRaȡֵΧ( )
A.(-,2 B. -2,2 C.(-2,2 D.(-,-2)
2.()κf(x)=x2-x+a(a>0),f(m)<0,f(m-1)ֵΪ( )
A. B.
C.Ǹ D.㶼п
3.()֪κf(x)=4x2-2(p-2)x-2p2-p+1,[-11]ٴһʵc,ʹf(c)>0,ʵpȡֵΧ_________.
4.()κf(x)ĶϵΪҶʵxf(2+x)=f(2-x),f(1-2x2)
5.()֪ʵtϵʽ (a>0a1)
(1)t=ax,y=f(x)ıʽ;
(2)x(0,2 ʱyСֵ8axֵ.
6.()κy=mx2+(m-3)x+1ͼxĽһԭҲ࣬mȡֵΧ.
7.()κf(x)=px2+qx+rʵpqr =0,m>0,֤
(1)pf( )<0;
(2)f(x)=0(01)ںн.
8.()һСװijַ£x()ۼP(Ԫ/)֮ĹϵΪP=160-2x,xijɱR=500+30xԪ.
(1)ó²ʱ»õ1300Ԫ?
(2)²Ϊʱɻ?ǶԪ?
ο
ѵų
⣺֪0,(-4a)2-4(2a+12)0,- a2
(1)- a<1ʱԭ̻Ϊx=-a2+a+6,-a2+a+6=-(a- )2+ .
a=- ʱxmin= ,a= ʱxmax= .
x .
(2)1a2ʱx=a2+3a+2=(a+ )2- ൱a=1ʱxmin=6,a=2ʱxmax=12,6x12.
, x12.
ѵѵ
һ1.a-2=0a=2ʱ,ʽΪ-4<0,.a=2,a-20ʱa ,-2
𰸣C
2.f(x)=x2-x+aĶԳΪx= ,f(1)>0,f(0)>0,f(m)<0,m(0,1),
m-1<0,f(m-1)>0.
𰸣A
3.ֻf(1)=-2p2-3p+9>0f(-1)=-2p2+p+1>0-3
𰸣(-3 )
4.f(2+x)=f(2-x)֪x=2ΪԳᣬھԳϽĵС
|1-2x2-2|<|1+2x-x2-2|,-2
𰸣-2
5.⣺(1)loga logat-3=logty-3logta
t=ax֪x=logatʽx-3= ,
logay=x2-3x+3y=a (x0).
(2)u=x2-3x+3=(x- )2+ (x0),y=au
0
u=(x- )2+ (02 Ӧֵu(02 ϲֵ.
a>1,Ҫʹy=auСֵ8u=(x- )2+ ,x(0,2 ӦСֵ
൱x= ʱumin= ,ymin= =8a=16.a=16,x= .
6.⣺f(0)=1>0
(1)m<0ʱκͼxҷֱy࣬.
(2)m>0ʱ 0
mȡֵΧ{m|m1m0}.
7.֤(1) ,f(x)Ƕκp0,m>0,ԣpf( )<0.
(2)⣬f(0)=r,f(1)=p+q+r
ٵp<0ʱ(1)֪f( )<0
r>0,f(0)>0,f( )<0,f(x)=0(0 )н;
r0,f(1)=p+q+r=p+(m+1)=(- )+r= >0,
f( )<0,f(x)=0( ,1)н.
ڵp<0ʱ֤ͬ.
8.⣺(1)ó»Ϊy,ê
y=(160-2x)x-(500+30x)=-2x2+130x-500
y1300֪-2x2+130x-5001300
x2-65x+9000(x-20)(x-45)020x45
൱²20~45֮ʱ»1300Ԫ.
(2)(1)֪y=-2x2+130x-500=-2(x- )2+1612.5
xΪx=3233ʱyȡֵΪ1612Ԫ
൱²Ϊ3233ʱɻ1612Ԫ.
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