TTV: Bài toán khó của thầy Văn Như Cương tại Olympic 1982! Niềm tự hào toán học Việt Nam.

Wish everyone a happy watching video -----+++++ DONATE me: https://nhantien.momo.vn/0965323988 or #IMO#baitoanIMO1982#GSvannhucuong# Mr. Van Nhu Cuong's difficult math problem at the 1982 Olympics Mr. Cuong's geometry problem was so difficult that many countries wanted to remove it from the exam and when it was kept, the judges changed it to make it easier. At the "Imprint" exhibition organized by students of Luong The Vinh High School (Hanoi) on November 20, besides thousands of photos and hundreds of books, there was the Olympic math problem of Mr. Van Nhu Cuong - former Chairman of the Board of Directors of the school. Previously, at the International Mathematical Olympiad (IMO) in 1982, the Vietnamese team was led by Professor Hoang Xuan Sinh and Deputy Head of the delegation, Professor Doan Quynh. Vietnam contributed a geometry problem prepared by Mr. Van Nhu Cuong. Professor Tran Van Nhung shared many times that Mr. Cuong's problem was very difficult and unique. Many countries wanted to remove it from the six problems of the exam. But Hungarian professor and academician R. Alfred, President of IMO that year, decided to keep it and praised it as "very good". However, the problem in the official exam had its conditions changed. This was said to make the problem easier. That year, only 20 candidates of the exam solved this problem, including Le Tu Quoc Thang of Vietnam - who won the gold medal with a score of 42/42. The Vietnamese delegation ranked 5th out of 30 participating countries. Original problem by Mr. Van Nhu Cuong Once upon a time, there was a square village with each side 100 km long. There was a river running around the village. Any point in the village was no more than 0.5 km away from the river. Prove that there are two points on the river whose distance as the crow flies is not more than 1 km, but the distance along the river is not less than 198 km. (Assume the river bed is not significantly wide). Official problem of IMO 1982: Given a square S with side length 100. L is a non-intersecting zigzag line formed by line segments A0A1, A1A2…, A(n-1)An with A0 ≠ An. Suppose that for every point P on the perimeter of S there exists a point in L which is not more than 1/2 away from P. Prove that: There exist two points X and Y in L such that the distance between X and Y does not exceed 1, and the length of the zigzag line L between X and Y is not less than 198. Difference: The official exam has changed the condition compared to the original problem of Mr. Van Nhu Cuong: "Any point in the village is not more than 0.5 km from the river" to "Any point on the perimeter of the village is not more than 0.5 km from the river". Don't forget to subscribe to the channel to update interesting videos, thank you everyone. Interesting Math: Channel sharing interesting things in math such as: fun puzzles, calculation methods, calculation tips, quick math problems, IQ test, fun math problems, tricky math problems and even math mistakes... Subscribe to the channel at:    / @toánthúvị   Email: [email protected]