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SRMC 2015 inequality P1
Source:
4/3/2015
Given positive real numbers
a
,
b
,
c
,
d
a,b,c,d
a
,
b
,
c
,
d
such that \frac{a}{b}+\frac{b}{c}+\frac{c}{d}+\frac{d}{a}=6 \text{and} \frac{b}{a}+\frac{c}{b}+\frac{d}{c}+\frac{a}{d}=36.Prove the inequality
a
2
+
b
2
+
c
2
+
d
2
>
a
b
+
a
c
+
a
d
+
b
c
+
b
d
+
c
d
.
{{a}^{2}}+{{b}^{2}}+{{c}^{2}}+{{d}^{2}}>ab+ac+ad+bc+bd+cd.
a
2
+
b
2
+
c
2
+
d
2
>
ab
+
a
c
+
a
d
+
b
c
+
b
d
+
c
d
.
inequalities
algebra