问题 选择题
定义在R上函数f(x)满足f(0)=0,f(x)+f(1-x)=1,且f(
x
5
)=
1
2
f(x)
当0≤x1<x2≤1时,f(x1)≤f(x2),则f(
1
2011
)
=(  )
A.
1
2
B.
1
16
C.
1
32
D.
1
64
答案

∵f(x)+f(1-x)=1

令x=1得的f(1)=1,x=

1
2
得f(
1
2
)=
1
2

∵f(

x
5
)=
1
2
f(x)得,

f(

1
5
)=
1
2
f(1)=
1
2
,f(
1
25
)=
1
2
f(
1
5
)=
1
4
,f(
1
125
)=
1
2
f(
1
25
)=
1
8
,f(
1
625
)=
1
2
f(
1
125
)=
1
16
,f(
1
3125
)=
1
2
f(
1
625
)=
1
32

由f(

x
5
)=
1
2
f(x)得

f(

1
10
)=
1
2
f(
1
2
)=
1
4
,f(
1
50
)=
1
2
f(
1
10
)=
1
8
,f(
1
250
)=
1
2
f(
1
50
)=
1
16
,f(
1
1250
)=
1
2
f(
1
250
)=
1
32

∵0≤x1<x2≤1时,f(x1)≤f(x2),

由f(

1
3125
)≤f(
1
2011
)≤f(
1
1250
)及f(
1
3125
)=f(
1
1250
)=
1
32
得f(
1
2011
)=
1
32

故选C.

阅读理解与欣赏
填空题