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Taiwan APMO Prelininary
2021 Taiwan APMO Preliminary First Round
1
1
Part of
2021 Taiwan APMO Preliminary First Round
Problems
(1)
Min of (|b|+|c|)/a
Source: 2021 Taiwan APMO Preliminary First Round
11/21/2020
Let the three roots of
x
3
+
a
x
+
1
=
0
x^3+ax+1=0
x
3
+
a
x
+
1
=
0
be
α
,
β
,
γ
\alpha,\beta,\gamma
α
,
β
,
γ
where
a
a
a
is a positive real number. Let the three roots of
x
3
+
b
x
2
+
c
x
−
1
=
0
x^3+bx^2+cx-1=0
x
3
+
b
x
2
+
c
x
−
1
=
0
be
α
β
,
β
γ
,
γ
α
\frac{\alpha}{\beta},\frac{\beta}{\gamma},\frac{\gamma}{\alpha}
β
α
,
γ
β
,
α
γ
. Find the minimum value of
∣
b
∣
+
∣
c
∣
a
\dfrac{|b|+|c|}{a}
a
∣
b
∣
+
∣
c
∣
.
algebra