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Hungary-Israel Binational
2005 Hungary-Israel Binational
2
functions defined by Fibonacci numbers
functions defined by Fibonacci numbers
Source: 16-th Hungary-Israel Binational Mathematical Competition 2005
March 29, 2007
function
algebra unsolved
algebra
Problem Statement
Let
F
n
F_{n}
F
n
be the
n
−
n-
n
−
th Fibonacci number (where
F
1
=
F
2
=
1
F_{1}= F_{2}= 1
F
1
=
F
2
=
1
). Consider the functions
f
n
(
x
)
=
∥
.
.
.
∥
∣
x
∣
−
F
n
∣
−
F
n
−
1
∣
−
.
.
.
−
F
2
∣
−
F
1
∣
,
g
n
(
x
)
=
∣
.
.
.
∥
x
−
1
∣
−
1
∣
−
.
.
.
−
1
∣
f_{n}(x)=\parallel . . . \parallel |x|-F_{n}|-F_{n-1}|-...-F_{2}|-F_{1}|, g_{n}(x)=| . . . \parallel x-1|-1|-...-1|
f
n
(
x
)
=∥
...
∥
∣
x
∣
−
F
n
∣
−
F
n
−
1
∣
−
...
−
F
2
∣
−
F
1
∣
,
g
n
(
x
)
=
∣...
∥
x
−
1∣
−
1∣
−
...
−
1∣
(
F
1
+
.
.
.
+
F
n
F_{1}+...+F_{n}
F
1
+
...
+
F
n
one’s). Show that
f
n
(
x
)
=
g
n
(
x
)
f_{n}(x) = g_{n}(x)
f
n
(
x
)
=
g
n
(
x
)
for every real number
x
.
x.
x
.
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