Search found 8 matches

by prottoydas
Sat Mar 17, 2018 2:28 pm
Forum: Junior Level
Topic: BDMO 2016: National Junior/2
Replies: 5
Views: 6050

Re: BDMO 2016: National Junior/2

very easy problem
by prottoydas
Thu Mar 15, 2018 12:31 pm
Forum: International Mathematical Olympiad (IMO)
Topic: IMO 2017 P4
Replies: 4
Views: 6520

Re: IMO 2017 P4

very easy problem for IMO
by prottoydas
Tue Mar 13, 2018 9:13 pm
Forum: National Math Olympiad (BdMO)
Topic: National BDMO Secondary P8
Replies: 4
Views: 2109

Re: National BDMO Secondary P8

[After Tasnood] In the cyclic $BCFE$ quadrileteral,we get $/angleBFC=120$.$/angleDFE=90$ so,$/angleCFD=30$.Now $FD$ bisects $/angleBFC$ then https://artofproblemsolving.com/community/c5h472280p2644107 [it is a well known geometry problem from AIME 2012.So,sad that it is th 8th problem in 2012 nation...
by prottoydas
Sat Mar 03, 2018 4:34 pm
Forum: National Math Olympiad (BdMO)
Topic: BdMO 2017 junior/4
Replies: 11
Views: 3588

Re: BdMO 2017 junior/4

n^3-n=n^2(n-1) Here we have 2 cases. Case 1:n^2 is divisible by 73 and n-1 is divisible by 27. Now n is the form of 73k. We get 73k-1 is congruent to 0(mod27) Or,-(8k+1) is congruent to 0(mod27) Or, 8k is congruent to 26 (mod27) Or, 4k is congruent to 13 (mod27) Or, 4k is congruent to 40 (mod27) Or,...
by prottoydas
Sat Feb 24, 2018 12:48 pm
Forum: National Math Olympiad (BdMO)
Topic: BDMO NATIONAL Junior 2016/04
Replies: 8
Views: 2760

Re: BDMO NATIONAL Junior 2016/04

hello protaya and prottoy das are the same person.I have forgot the password of protaya das so i am using the prottoy das id.
by prottoydas
Thu Feb 01, 2018 8:14 pm
Forum: Geometry
Topic: A hard Geometry Problem
Replies: 4
Views: 26959

A hard Geometry Problem

$\triangle ABC$ is an acute angled triangle with orthocenter $H$ and circumcenter $O$. Prove that, $\angle CAH =\angle BAO$.