## A proposed problem of IMO

Discussion on International Mathematical Olympiad (IMO)
nafistiham
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### Re: A proposed problem of IMO

Phlembac Adib Hasan wrote:Ekta proof-er jonno eto zhamela!Ok, oi proof baad.Arecta proof diteci.
nafistiham wrote:
and, i am seeing that one's proof says it is possible another's says it is not.would anyone clear who's right ?

i see no bug in Sourav da's proof, but could not find any in adib's either (too dumb to read the giant proof at a strech)
misunderstood.
Last edited by nafistiham on Sat Feb 04, 2012 7:13 pm, edited 1 time in total.
$\sum_{k=0}^{n-1}e^{\frac{2 \pi i k}{n}}=0$
Using $L^AT_EX$ and following the rules of the forum are very easy but really important, too.Please co-operate.

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### Re: A proposed problem of IMO

@Tiham Vaia, my proof also says either all $c_i$s are non-positive, or non-negative.I only showed that it is impossible to follow the given condition if all $c_i$s are not of same sign.And a question:My Bangla Front is not working in Forum. What can I do?
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nafistiham
Posts: 829
Joined: Mon Oct 17, 2011 3:56 pm
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### Re: A proposed problem of IMO

$\sum_{k=0}^{n-1}e^{\frac{2 \pi i k}{n}}=0$
Using $L^AT_EX$ and following the rules of the forum are very easy but really important, too.Please co-operate.