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Putnam
2003 Putnam
4
Putnam 2003 A4
Putnam 2003 A4
Source:
June 23, 2011
Putnam
quadratics
function
calculus
derivative
inequalities
absolute value
Problem Statement
Suppose that
a
,
b
,
c
,
A
,
B
,
C
a, b, c, A, B, C
a
,
b
,
c
,
A
,
B
,
C
are real numbers,
a
≠
0
a \not= 0
a
=
0
and
A
≠
0
A \not= 0
A
=
0
, such that
∣
a
x
2
+
b
x
+
c
∣
≤
∣
A
x
2
+
B
x
+
C
∣
|ax^2+ bx + c| \le |Ax^2+ Bx + C|
∣
a
x
2
+
b
x
+
c
∣
≤
∣
A
x
2
+
B
x
+
C
∣
for all real numbers
x
x
x
. Show that
∣
b
2
−
4
a
c
∣
≤
∣
B
2
−
4
A
C
∣
|b^2- 4ac| \le |B^2- 4AC|
∣
b
2
−
4
a
c
∣
≤
∣
B
2
−
4
A
C
∣
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