已知函数f(x)是偶函数,且f(x0在[0,正无穷大)上是增函数,
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由题意可得定义域是R
(1)当ax-1>=0时,即a>=1/x,f(ax-1)<=f(x-2)=f(2-x),
得ax-1<=2-x,
x(a+1)<=3,a+1<=3/x,a<=3/x-1,在[1/2,1]上a<=MIN(3/x-1)=2,
即a<=2
又有a>=1/x,得a>=2,即a=2
(2)当ax-1<0,即a<1/x,a<1,
f(ax-1)<=f(x-2),
ax-1>x-2,
a-1>-1/x,a>1-1/x,a>0,所以0<a<1
综上所述,0<a<1或a=2
(1)当ax-1>=0时,即a>=1/x,f(ax-1)<=f(x-2)=f(2-x),
得ax-1<=2-x,
x(a+1)<=3,a+1<=3/x,a<=3/x-1,在[1/2,1]上a<=MIN(3/x-1)=2,
即a<=2
又有a>=1/x,得a>=2,即a=2
(2)当ax-1<0,即a<1/x,a<1,
f(ax-1)<=f(x-2),
ax-1>x-2,
a-1>-1/x,a>1-1/x,a>0,所以0<a<1
综上所述,0<a<1或a=2
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