#Help with proving the above inequality

51 messages · Page 1 of 1 (latest)

brave lake
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We have to prove the inequality using A.M>G.M but I have no idea how to split the terms to do so

craggy hemlockBOT
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wispy flicker
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Permutation ineq might play a role here

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,w permutation inequality

wispy flicker
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Bruh

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Well if I remember correctly, it’s that …

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Ok for monotonic increasing sequences $a_n, b_n$ we have that $$\sum_{k=1}a_kb_k \geq \sum_{k=1}a_kb_{\pi(k)}$$ for any permutation $\pi$ on ${1,…,n}$

ionic crownBOT
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ℝανι-sαη

wispy flicker
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You can assume WLOG that b>a

brave lake
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Wait so it can't be done through the sequence and series formulae?

brave lake
drifting solstice
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See if you can get some Information from the fact that a and b are natural numbers and a ≠b

brave lake
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I guess you have to separate a b times and b a times

drifting solstice
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I think not

brave lake
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To get a power b terms u have to separate it b times

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Like for example if it was a²b² we would write a/2 + a/2 + b/2 + b/2

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Then do the am >gm method

drifting solstice
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Try to do some algebraic manipulations from AM>GM

brave lake
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I mean we can write it as a/b + a/b ... b times

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But I'm not getting anything from that method

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Unless u need to shift the powers or smth

drifting solstice
brave lake
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How though

drifting solstice
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Full solutions aren't allowed, sadly, you can only get hints

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You have to do the work yourself

brave lake
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No but tell me a method

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How would u raise the terms?

drifting solstice
brave lake
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I tried algebraic manipulation but I got no results

brave lake
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Like squaring both sides of some sorts

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?

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If we want to get the terms we have to split a b times and b a times

drifting solstice
brave lake
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Hmm

drifting solstice
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Try ab also

brave lake
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Wait ur using the am>gm relation right?

brave lake
drifting solstice
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How one can prove it without AM>GM

brave lake
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Idk the guy before did something w/ p and c

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I'll try it

ebon lavaBOT
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@brave lake

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brave lake
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+close

ebon lavaBOT
# brave lake +close
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