MathDB
Problems
Contests
National and Regional Contests
Croatia Contests
Croatia National Olympiad
2004 Croatia National Olympiad
Problem 3
absolute value inequality (Croatian MO 2004 1st Grade P3)
absolute value inequality (Croatian MO 2004 1st Grade P3)
Source:
April 8, 2021
absolute value
inequalities
Problem Statement
Prove that for any three real numbers
x
,
y
,
z
x,y,z
x
,
y
,
z
the following inequality holds:
∣
x
∣
+
∣
y
∣
+
∣
z
∣
−
∣
x
+
y
∣
−
∣
y
+
z
∣
−
∣
z
+
x
∣
+
∣
x
+
y
+
z
∣
≥
0.
|x|+|y|+|z|-|x+y|-|y+z|-|z+x|+|x+y+z|\ge0.
∣
x
∣
+
∣
y
∣
+
∣
z
∣
−
∣
x
+
y
∣
−
∣
y
+
z
∣
−
∣
z
+
x
∣
+
∣
x
+
y
+
z
∣
≥
0.
Back to Problems
View on AoPS