Chapter 37 (1/2)
”Be magnanimous. If you're late, you'll be late. Can't you just walk in the front door?”
Gan!
I'm not afraid to disturb your class.
Isn't it international practice for late comers to enter through the back door?
A pair of eyes to see over, even if the skin is still relatively thick, Hao Yun also a little embarrassed.
Just as he was hesitating whether to walk through the front door again, Li Xuesong on the stage coughed and continued with a straight face.
”What about homework?”
Do, homework?
On hearing this, Hao Yun was embarrassed.
”Well, I forgot.”
Forgot to bring it?
ha-ha!
If you don't write it, you don't write it. You still make such low-level excuses.
Looking at Hao Yun with a smile, Li Xuesong continued: ”forget to bring it? OK. You mean it's written? Anyway, there's only one question. Is it OK for you to write it now? ”
With that, he tapped on the blackboard with his index finger.
”Come here and write.”
Hearing the old professor's words, there was a commotion in the class, and many people began to whisper.
Hao Yun, who was standing in the back row, could not hear clearly what they were talking about. He just wanted to make complaints about the old professor. I didn't do anything hurtful, but I was a minute or two late. As for being so difficult.
Looking at Lao Li's smiling face, he knew that he was doomed today.
In his heart, he cursed the second product who had complied with his draft. Hao Yun sighed and finally walked towards the platform.
As he passed the front row, he noticed that Zheng Xueqian was shaking his eyes wildly to deliver a message and poking the screen of his mobile phone, as if to signal him to read wechat.
Are you crazy?! Actually come up? No one can write that question!]
Although I can guess that this good brother probably sent the answers to his homework to himself, he has already come here, and obviously he has no chance to take out his mobile phone.
Hao Yun gave him a reassuring look and made eye contact.
Don't worry, I'm fine
On the ”self-confident” eyes, Zheng Xueqian was blinded for a moment.
what the fuck?
What does this guy mean?
Can't... Really write it out?
It's impossible!
The problem that he Shen didn't write
The touch of his eyes was just a moment. Before he could confirm whether he was wrong, Zheng Xueqian watched Hao Yun stand on the platform.
After taking the chalk from Lao Li's hand, Hao Yun stood in front of the blackboard for a while and suddenly turned back with embarrassment.
”Well, what's the title... I didn't memorize it.”
On hearing this sentence, Li Xuesong laughed and said, ”I'll see when you're going to perform. I pointed to the platform with my chin.”.
”There are so many on the table, you can copy one at will.”
A copy is OK
Aren't you afraid I'll see the answer?
Hao Yun, who picked up the top assignment, muttered a few words in his heart. However, just after opening it, he was stunned.
Good guy, I wrote a ”solution”.
Is this not going to be divided as usual?
At least hide the book down!
Another look at the name, it's actually Liang Ziyuan's.
Silently wrote down the title, Hao Yun was very generous to help him put the homework to the bottom.
Taking a panoramic view of the student's small movements, Li Xuesong laughed and did not tear them down. He just picked his eyebrows and continued.
”Now you know the title?”
”Well, I remember.”
”Remember? OK, then stop talking nonsense and start writing quickly
Originally, it was not a particularly difficult topic. Even there were only a few letters. All the information in the stem of the topic could be explained in two sentences.
Hao Yun didn't think much about it, so he turned around and copied the title on the blackboard, and then read it carefully from beginning to end again.
However, this copy doesn't matter.
When he copied the title and read it again, the whole person was stunned.
Let positive integers a and B satisfy (a) ²+ b ²）/（ AB + 1) = k ∈ n, proving that K is the square of a positive integer
good heavens.
This question
A little familiar?
Seeing Hao Yun's inaction for a long time, Li Xuesong thought he couldn't, so he joked with a smile: ”if you can write it out, you won't have to go to my class in the future. I'll give you all the credits.”
Hao Yun swallowed his saliva and couldn't believe it.
”... really?”
”Oh, I need to lie to you?”
Then I really wrote
After confirming that this guy didn't seem to be saying ironic things, Hao Yun hesitated for a moment. Finally, he pasted the chalk on the blackboard and started to write.
Let K not be the square of a positive integer, then a ≠ B
Consider the Diophantine equation a ²－ kab+（b ²－ k) If a = B, then k = 1 can be deduced, which contradicts the hypothesis
Let a 〉 B 〉 0 and take a set of solutions (A0, B0) to minimize A0 + B0
Although he copied this question in the draft book before, Hao Yun never took the time to read it carefully, otherwise he would not be surprised.
And the reason for surprise is simple.
Because this is not only an original question, but also the sixth question of the 1988 IMO International Mathematics Competition on the earth!
As for why he knew
It's not because he participated in that competition, but because just yesterday, he saw it in the advanced mathematics textbook full of notes, and finally did it himself.
He even remembered that the problem was copied in the blank space at the end of the page of Veda's theorem.
According to Professor Lu's remarks, none of the examiners made this seemingly simple number theory question. Finally, they asked four number theory experts from Australia, the host of the contest, for help, but they were at a loss for a long time.
Because the experts can't work out this problem within the prescribed time, this problem has become a legend.
A total of hundreds of contestants, only a dozen of them wrote their answers in the end, and one of them even won a special prize from the main examination committee for his beautiful answers.
At the moment, he is writing on the blackboard, which is the ”standard answer” that was awarded the special prize that year.