Inequality

Prove the following
if x,y,z>0

\frac{2}{x+y}+\frac{2}{y+z}+\frac{2}{x+z}\geq \frac{9}{x+y+z}

7 Answers

11
Mani Pal Singh ·

may i give the answer now
or
someone wanna try??

39
Dr.House ·

wait

39
Dr.House ·

39
Dr.House ·

http://targetiit.com/iit_jee_forum/posts/prove_it_imp_4_jee_8336.html

62
Lokesh Verma ·

anotehr proof

let (x+y)/2 = a

(x+z)/2 = b

(z+y)/2 = c

Apply AM GM inequality to a, b, c

1
Philip Calvert ·

perhaps the same thing here :

http://www.mathlinks.ro/Forum/viewtopic.php?t=132021

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11
Mani Pal Singh ·

sir this can also be done by CAUCHY

we can write it as

\frac{(\sqrt{2})^{2}}{x+y} + \frac{(\sqrt{2})^{2}}{y+z} +\frac{(\sqrt{2})^{2}}{x+z}\geq \frac{(3\sqrt{2})^{2}}{2(x+y+z)}

\frac{(\sqrt{2})^{2}}{x+y} + \frac{(\sqrt{2})^{2}}{y+z} +\frac{(\sqrt{2})^{2}}{x+z}\geq \frac{9}{x+y+z}

HENCE PROVED

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