Top Student

After class, Xu You was the first to rush to the podium.

"Teacher, the Laplace equation is invariant to inversion transformation, right?"

Hearing Xu You's question, Cao Quanli was also taken aback.

In Cao Quanli's teaching career, he has never heard of such a property.

"Xu You, what are you talking about?"

If someone else raised this inexplicable question, Cao Quanli would even directly ask him not to study the nature of this sounding heresy.

However, if it was Xu You who asked the question, it would be completely different.

In this year's CPhO finals, Xu Youke won the first place in the country with a perfect score.

In the year when Cao Quanli won the championship, he did not get full marks.

This year's final topic, Cao Quanli also did it himself.

It also doesn't get full marks at all.

For a child like Xu You, Cao Quanli can only show respect.

"Teacher, let me just write on the blackboard."

"Well, write it down and let me see."

During normal get out of class time, Cao Quanli would often discuss issues with students.

Cao Quanli would naturally agree to Xu You's request.

At this time, there was no atmosphere of finishing get out of class in the classroom.

Everyone looked at the blackboard, wondering what exactly Xu You and Cao Quanli were discussing.

"Hey, do you know what kind of pull or pull that Youshen said?"

Luo Wenkun listened to the general idea, and asked Lin Shi puzzled.

Lin Shi shook her head, also looking puzzled.

After that, Xu You wrote out his entire derivation process.

Because the classroom this time has four large blackboards that can move, there will be no situation where you can't write.

Xu You can write with confidence.

"Teacher, it is using the inversion method to deduce that the Laplace equation is invariant to inversion transformation. There are also inversion method textbooks, that is, in "Continuum Electrodynamics", I remember it should be page 13, but There is no proof process above, I just proved it."

"The inverse method... there is indeed such a method."

Cao Quanli tried his best to recall, and indeed he had some impression of this method.

As for whether it is on page 13 of that "Continuum Electrodynamics".

Naturally, Cao Quanli couldn't remember.

"From the Laplace equation in the spherical coordinate system, and there are two inversion expressions, this equation can be deduced simultaneously..."

"For the angular part of Laplace's equation, there is also..."

"In this way, the Laplace equation after the inverse transformation is obtained..."

Xu You explained to Cao Quanli according to the process he wrote on the blackboard.

Listening to this, Cao Quanli couldn't help but frowned.

For some reason, Cao Quanli always felt like he was listening to mathematics and competing for class.

"Compared with the original Laplace equation, it can be seen that after the coefficients are reduced, the two forms are exactly the same, and the relationship between the solutions can be determined according to the inversion transformation formula."

After explaining the whole derivation process, Cao Quanli seemed half-understandable.

As for the students under the podium...

He had no idea what Xu You was talking about.

"Xu You, are you using the number competition method?"

"Yes, it is some methods learned in the math competition. Mathematical physics is interlinked. Teacher, using mathematical methods to help solve physics problems should be no problem, right?"

At this time, Cao Quanli was also a little embarrassed.

Cao Quanli did not dare to say that Xu You's method was wrong, nor did he dare to call Xu You's method correct.

Cao Quanli has not studied the number competition specifically, and is not very familiar with some methods in the number competition.

After all, if Xu You's method is really correct, it will indeed save a lot of time in solving problems.

When everyone saw such a scene, they were also a little happy in their hearts.

Isn't Cao Quanli quite awesome at ordinary times?

Why was Xu You so questioned that he dared not answer.

Lin Shi also felt much more comfortable.

Sure enough, Xu You must not be viewed with normal eyes.

Even Cao Quanli, the head coach of the national team, could not judge whether Xu You's proof process was correct.

"Well, I'll ask a teacher to come over to confirm. I don't dare to be accurate about the mathematical methods used in it."

Cao Quanli finally let go of his face and decided to seek off-court assistance.

After a while, another teacher came into the classroom.

"This is Mr. Qiao Sen. He was also the champion of Wujing, and he is a double-country player in Wujing and Mashujing. He has also led the national team for many times. Mr. Qiao Sen, please take a look at the derivation process of this student."

It is indeed difficult for people who have not studied mathematics competitions to understand such complex mathematical knowledge.

Teacher Qiao Sen hadn't looked at the questions yet, but just looked at the problem-solving process on the blackboard, and his face beamed with joy.

"Son, is this your proof?"

Xu You nodded upon hearing this.

"When I was in class just now, I suddenly thought of this method, and I proved it easily. I don't know if it's right, and I don't know if it can be used."

Hearing Xu You's words, Qiao Sen smiled even more happily.

"Haha, we Huaxia finally have a good seedling who can learn both physical and mathematical knowledge well! Not bad, good young people!"

"Mr. Qiao, have you seen this method?" Cao Quanli asked in surprise.

"If I'm not mistaken, this is a proof that Laplace's equation is invariant to inversion transformation?"

"Yes, it's that labrador, whether you want a sex change certificate or not." Luo Wenkun replied quickly.

Hearing what Luo Wenkun said, there was a burst of laughter in the classroom.

"Seven years ago, when I was talking about a topic on electromagnetism, there was also a child who introduced such a property. It's just because the threshold is too high, so it is not recommended for students who have not been exposed to math competitions."

"In other words, there is no problem with this process?" Cao Quanli asked in surprise.

Qiao Sen carefully watched the whole proof process again, and nodded solemnly.

"There is no problem with the proof process. And I have confirmed that it can also be used on IPhO. As long as the process is completely proved on the test paper, no point will be deducted. This method is indeed much faster than the conventional method. "

Seeing that Qiao Sen was so sure, Cao Quanli no longer had any worries.

"Since Teacher Qiao said that there is no problem, it must be usable. Teacher Qiao, do you want to promote this method as a common solution?"

"For those who have never studied mathematics, there is no need to master this method. It involves too much mathematics knowledge. Everyone knows that there is such a method, and there is no need to master it."

Although the entire proof process is not too long to be exaggerated, it is indeed difficult to recite it completely if you do not understand it.

If the proof is wrong because of some problems in the middle process, the loss outweighs the gain.

"That's right, then I'll wipe it off."

Seeing what Qiao Sen said, Cao Quanli also felt that he had regained some face.

After all, even if he was asked to explain it, he would not understand it.

Just treat it as Xu You's proprietary solution.

"Wait a minute, teacher, don't rub it yet!"