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IberoAmerican
1991 IberoAmerican
3
3
Part of
1991 IberoAmerican
Problems
(1)
Find f(18/1991)
Source: Iberoamerican Olympiad 1991
4/28/2007
Let
f
:
[
0
,
1
]
→
R
f: \ [0,\ 1] \rightarrow \mathbb{R}
f
:
[
0
,
1
]
→
R
be an increasing function satisfying the following conditions: a)
f
(
0
)
=
0
f(0)=0
f
(
0
)
=
0
; b)
f
(
x
3
)
=
f
(
x
)
2
f\left(\frac{x}{3}\right)=\frac{f(x)}{2}
f
(
3
x
)
=
2
f
(
x
)
; c)
f
(
1
−
x
)
=
1
−
f
(
x
)
f(1-x)=1-f(x)
f
(
1
−
x
)
=
1
−
f
(
x
)
. Determine
f
(
18
1991
)
f\left(\frac{18}{1991}\right)
f
(
1991
18
)
.
function
algebra proposed
algebra