In the quiet classroom, Xu Chuan was flipping through mathematics textbooks. Some of the thick stacks of books on his desk were mathematics textbooks borrowed from the library for the first and second grades of high school.
After all, so much time had passed that he had forgotten what the textbook looked like. If he wanted to read it, he had to read it from the beginning, so as not to miss any knowledge points and lose points in the exam, which would be embarrassing and embarrassing.
If a Fields Medal winner cannot get full marks in an ordinary high school competition, he might as well be reborn, smash his medals, and go home to grow sweet potatoes and raise pigs.
After more than an hour, the lunch break bell rang, and Teacher Gong, whom Song Kaiji said would be here soon, walked into the classroom.
"Hello, Teacher Gong."
"Hello, Teacher Gong."
In the classroom, the classmates who were reading and doing questions all said hello. Xu Chuan looked up and saw a man wearing gray and black plaid wool. He was not tall and wore a pair of glasses.
Completely different from Song Kaiji's almost half-bald hairstyle, Gong Rihui's hair is very thick. It's so thick that it makes people wonder whether he studied mathematics. It's so thick that it doesn't fit the concept of baldness in the impression of mathematics teachers.
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"Hello, Teacher Gong."
Xu Chuan also said hello respectfully. As a contestant who often participates in competitions, although they are not in the same subject, they still know each other.
Even though Mr. Gong’s thick hair doesn’t look like he’s studying mathematics, he has been leading the Mathematics Training Team of Xingcheng No. 1 Middle School for more than ten years. Some of his students have even won IMO gold medals.
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"Is Xu Chuan here? Come on, come up and do a question first."
Gong Rihui glanced at the classroom and saw an extra person in the classroom at a glance. He smiled and wrote a math problem on the blackboard with his backhand, and then directly named Xu Chuan.
He naturally knew this talented man who studied physics. Like Song Kaiji, he also felt that it was a pity for such a good young man to study physics.
I am so good at math in college, the foundation of all subjects!
Without mathematics, you can’t even calculate how much change you’ll get when buying groceries.
.......
"Find all pairs of positive integers (x, y) that satisfy xy=y^x-y. (^ means square)"
A mathematical problem was casually written on the blackboard by Gong Rihui. He threw the white chalk at the lecture table and looked at the physics genius in the audience with a smile.
Xu Chuan is no stranger to this approach of doing the questions first before entering the classroom.
Whether it was physics or mathematics, on the way to the competition, all he had to do was solve the problem. He had experienced this scene countless times. He was very familiar with it and was not nervous at all. He stood up straight away and prepared to do the problem.
"Brother Chuan, come on, go up and explode the anus, I support you!"
Next to him, Lu Tianrui, a little round-faced man, could be heard cheering in a low voice.
As soon as Xu Chuan stood up, his feet suddenly staggered when he heard this, and he barely managed to hold on to the table before he could stand still.
Are you such a pervert who plays math?
...
In front of the blackboard, Xu Chuan casually pulled out a piece of chalk from the podium. The question asked by Teacher Gong was difficult to say. In fact, most high school students could solve part of it.
Just like the last big question in the college entrance examination mathematics, the first small question is basically free and easy to solve.
But the difficulty increases exponentially in the following small questions.
The same goes for the question on the blackboard. In the college entrance examination, it belongs to the last one or two big questions. But in the competition, it is just a junior high school question after entry. It tests reasonable reasoning and analysis.
The ability to solve problems is of a more comprehensive nature.
What’s not difficult about it is that it’s easy to judge. Even a junior high school student can see that its first answer is (1,1).
.....
In front of the blackboard, Xu Chuan glanced at the question and thought about it for a few seconds before getting started.
"Solution: It is easy to find that x=y=1 satisfies the meaning of the question, so x=y=1 is the answer and has a solution. When the equation has a solution, x≥y must exist.