Found it very useful while solving the question bank at AoPS. Subscribed and Liked!

You from Switzerland?

I had a different method. I took BC,AC and AD to variables say a,b and x then I applied appolonius theorem on Triangle ABD to get AB then I took Ang BAE to be theta and applied cosine rule one ABE and ABC to get x^2=3b^2+a^2 then I put the value of x2 in AB to get sqrt(a^2-b^2) so AB^2+AC^2=a^2=BC^2 so by converse of pythagorean theorem ABC is right Triangled

Sir please make videos for every other topics

Which country?

5:10 and the answer is hmmmmm?? Kinda funny

Molom

What a beautiful introduction to symmedians!! Came here after reading chapter 4 of EGMO :))

Hello sir, just a question. You have won three bronze medals at the IMO. Why is it that you were not able improve to win a silver or gold medal in your second and third attempt. Grestly appreiciate your content and thanks in advice if you repond.

Cannot read this at all

Micheal Penn also has a nice way of explaining problems :>

I wonder how a good graph is the most important part of a geometry problem but no video and no mathematician shows their drawing. They all teach geometry problems using Geogebra and software and no one shows the entire paper process from scratch using a compass, a pen and a ruler. That is strange.

Bro im begginer what i need to do to go to imo what book and problem i need to learn especially problem

Iam fail in my country to join imo bro iam a sad loser

shitty handwriting

Padberg Ways

bro doesn't believe in digital board where he can omit if he overwrites on texts😂

Parisian Spur

The best explaination of this problem! Before this i tried to slove and got it so incorrect as i didn't read over an important detail and when i watched a video on the sol i had alot of doubts. This vedio made it so simple thank you ❤.

great proof, i think you forgot to set X to min({a}_{n+1}^{2^\alpha}) to ensure boundedness tho

5:52 But instead of proving that 5|n⁵-n I can directly say that n⁵-n is divisible by 5 because of fermats little theorem right??

Great story 👏

Don't give up.

I want his channel Excuse me

Hey Shef I am Struggling With Geometric Proofs Can You Provide Some Tips For That?

One of the most underrated channels about maths in youtube

What would be lesson 2? I can't find it

What does mean "homotherapy"? 1:28

one of the worst things in combi

I did it using mod 9 but same

in my solution the key is that xk=xk+9 k is in sub script

How BPB' Is collinear? And is P the midpoint, why? Help me

I am interested in those IMO problems that do not Require much of Knowledge to solve them. I call Them Street smart problems. Does anyone Have any suggestions in this regard? Thanks!

Amazing video. However, where can I find past test papers for olympiads for all levels?

Very elegant and clear explanation, the "pause&think" points inside the video are very pedagogical. Thanks.

Finally he rubbed his board

math

Hi, I want to participate in Imo too, but I don't know how to prepare and I'm at the starting level so you can give me some advice? What books do you recommend for the starting level?

Plz bro don't stop those videos

Nice

Nice

You have wrong answer

Good demostration

Bait ahh prob

Nice

Bosnia and Herzegovina won 3 gold medals! Congratulations, bro! 🎉👏

Bro never rubs his board

I think the problem was fairly nice but its very susceptible for very bashy solutions - and when you sit in a contest and see that a certain approach works you'd rather write that one fown and move on instead of trying to search for a nicer one. The bash I quickly came up with: Write a=k+c, for c in (0,1) then fo cases on c where we bound it between 1/m and 1/(m+1) and then you can do cases kn parity on k and m, so in total 4 cases, and get contradictions for all but k odd and m = 1, then you can write c=1-b and do again 2 cases on b (bound it again by reciprocals) and finally get contradictions