prove it (imp 4 jee)

Q Prove the following

x/y+z +y/x+z +z/x+y≥3/2

x,y,z are all >0

9 Answers

1
Manas ·

any condition on x andy given????

1
Mirka ·

This is d famous Nesbitts Inequality ....

its got some 25 proofs ...
[1]

11
Mani Pal Singh ·

mirka i have 2 [2]
u provide 23 [3]

1
Mirka ·

u can add 3 on both sides ..
then this becomes d A.M > H.M inequality dats d simplest proof !

EDIT : well, even i know juz 2

11
Mani Pal Singh ·

aage mirka ji

please elaborate a bit more in #3
i am weak in HM inequality

stillwaiting for 24 [3]

11
Mani Pal Singh ·

lets move on Proof No 2

we have

x2/xz+xy +y2/xy+yz + z2/xz+yz ≥3/2

Applying Cauchy we get

(x+y+z)2/2(x+y+z)≥3/2

x2+y2+z2≥xy+yz+xz
1/2[(x-y)2+(y-z)2+(x-z)2]≥0

hence proved

9
Celestine preetham ·

by symmetry minima if exists is at x=y=z

so put x=y=z u get ans≥3/2

1
Mirka ·

simplest proof -

and if u want the 25 proofs, here it is (from Kaymant sir's page) :

http://kaymant.googlepages.com/HowmanyproofsoftheNesbittsInequanlit.pdf

11
Mani Pal Singh ·

awesome post mirka
thanx 4 the link
now its party (inequality )time

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