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## #1 2012-09-23 21:59:31

hammana
Member
Registered: 2012-03-02
Posts: 48

### inequation a/b+b/c+c/d+d/a>=4

If a, b, c, d are 4 positive numbers, show that
a/b+b/c+c/d+d/a>=4

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## #2 2012-09-24 00:52:05

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,037

### Re: inequation a/b+b/c+c/d+d/a>=4

Hi hammana

Have you heard of the AM-GM inequality?

Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

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## #3 2012-09-24 04:35:30

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: inequation a/b+b/c+c/d+d/a>=4

Hi;

Have you left out some constraint on this problem?

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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