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International Contests
IMO Shortlist
1966 IMO Shortlist
46
46
Part of
1966 IMO Shortlist
Problems
(1)
Prove that f(a, b, c) = 4 max {1/a, 1/b, 1/c}
Source:
9/29/2010
Let
a
,
b
,
c
a,b,c
a
,
b
,
c
be reals and
f
(
a
,
b
,
c
)
=
∣
∣
b
−
a
∣
∣
a
b
∣
+
b
+
a
a
b
−
2
c
∣
+
∣
b
−
a
∣
∣
a
b
∣
+
b
+
a
a
b
+
2
c
f(a, b, c) = \left| \frac{ |b-a|}{|ab|} +\frac{b+a}{ab} -\frac 2c \right| +\frac{ |b-a|}{|ab|} +\frac{b+a}{ab} +\frac 2c
f
(
a
,
b
,
c
)
=
∣
ab
∣
∣
b
−
a
∣
+
ab
b
+
a
−
c
2
+
∣
ab
∣
∣
b
−
a
∣
+
ab
b
+
a
+
c
2
Prove that
f
(
a
,
b
,
c
)
=
4
max
{
1
a
,
1
b
,
1
c
}
.
f(a, b, c) = 4 \max \{\frac 1a, \frac 1b,\frac 1c \}.
f
(
a
,
b
,
c
)
=
4
max
{
a
1
,
b
1
,
c
1
}
.
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