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10th problem of BdMO'10
Posted: Wed Dec 15, 2010 3:21 pm
by AntiviruShahriar
$131$ টি ধনাত্নক পুর্ণ সংখ্যার এক্তি সেতে যেকনো সংখ্যার মৌলিক উত্পাদকগলো $42$ এর চেয়ে ছোট। দেখাও যে এই সেট থেকে এমন চারটি সংখ্যা নির্বাচন করা যাবে যেন তাদের গুণফল একটি পুর্ণবর্গ সংখ্যা হয়।
এইটা আমি National Math Olympiad (BdMO) এর পরীক্ষার দিন দেখার পর আর তাকাইও নাই।
মনে হয় পারব না। প্রথমে কেউ হিন্তস দাও। তারপর solution টা hidden করে রাখো।
Re: 10th problem of BdMO'10
Posted: Wed Dec 15, 2010 4:11 pm
by Moon
এইটা একটা আইএমও সমস্যার পরিবর্তিত রূপ।
Hint:
Re: 10th problem of BdMO'10
Posted: Thu Dec 16, 2010 1:26 am
by kamrul2010
Moon wrote:এইটা একটা আইএমও সমস্যার পরিবর্তিত রূপ।
Hint:
হিহিহিহি! মজা পাইসি!
Re: 10th problem of BdMO'10
Posted: Thu Dec 16, 2010 1:47 am
by AntiviruShahriar
কোন সালের??????আমি আই এম অ এর খুব কম ই করসি......।মুন ভাইয়ার হিন্ট তা সুন্দর হইসে............
Re: 10th problem of BdMO'10
Posted: Thu Dec 16, 2010 2:52 pm
by tushar7
Moon wrote:এইটা একটা আইএমও সমস্যার পরিবর্তিত রূপ।
Hint:
does that mean PHP ?!
Re: 10th problem of BdMO'10
Posted: Thu Dec 16, 2010 8:57 pm
by Hasib
Pigone hole principal diya korte hoy. Problem solving strategies boi tate dekhci bole mone pore
Re: 10th problem of BdMO'10
Posted: Sat Dec 24, 2011 4:33 pm
by sm.joty
Re: 10th problem of BdMO'10
Posted: Sun Dec 25, 2011 11:10 am
by sourav das
[By Different letters consider different elements]
There are 13 primes less then 42.Let the set be $A$. Now define a function $f$ such that for any $a,b \in A$ ; $f(ab)=$Product of those $P_i < 42$ such that $ab$ has odd power of those $P_i$ in it's prime power factorization(Let denote it by PPF).Define $f(ab)=1$ if $ab$ is a perfect square. Now denote that if $f(ab)=f(cd)$ then $abcd$ is a perfect square[As $abcd$ will have all even parity of power of all $P_i$ ]....(i).And also denote that if $f(ab)=f(ac)$ then $f(bc)=1$...(ii)[As in PPF of $b$ and $c$ both have same parity of power in all of it's prime ]. Now we'll consider 4 cases:
** Case 1:
** Case 2:
** Case 3:
**Case 4:
Please inform me if you find any bug.
And please inform me about the similar IMO problem.
And i still couldn't use the 'not equal sign '
Re: 10th problem of BdMO'10
Posted: Thu Dec 29, 2011 12:11 am
by *Mahi*
There was a similar problem of IMO 1985-4, solved that months ago
And use \not tag. That works on most PCs. If that doesn't work , there are some special cases like $\neq$
Re: 10th problem of BdMO'10
Posted: Wed Mar 07, 2018 11:11 pm
by samiul_samin
*Mahi* wrote: ↑Thu Dec 29, 2011 12:11 am
There was a similar problem of IMO 1985-4, solved that months ago
And use \not tag. That works on most PCs. If that doesn't work , there are some special cases like $\neq$
The problem
IMO 1985 #4 is harder than the national one.But,in that problem how many times do I need to use
PHP?I have seen the solution from TAACOPS and AoPS but didn't understand the solution fully.
I also want to solve this problem by using
PHP not by using
function.