Chapter 30 That, This... Green Function?

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The beautiful teacher, Wang Lili, paused for a moment and then began, "Um... Today, I'm going to teach you some knowledge about mathematical physics equations. Of course, it won't be the homogeneous equations you've learned in class but rather..."

"Today's key content: the Green Function method for the two-dimensional Laplace equation..."

As soon as these words were out, the class erupted in groans.

Ye Kaifu finally understood why the first three rows were empty.

This course must be a bomb!

The usual final questions in math exams, such as Fourier Transforms, orthogonal expansions, ordinary differential equations, and so on, had become routine tools here. Could it not be difficult?

Without saying much more, the teacher officially began the class.

"Dear students, I believe you've all learned homogeneous partial differential equations and non-homogeneous partial differential equations. Due to time constraints, we're not going to review them here..."

Ye Kaifu habitually glanced at Zhang Yuan and found this god-like figure was still lost in thought, unaware of what he was pondering.

Wait.

He seemed to be asleep!

Asleep, really asleep!

Haha!

Ye Kaifu almost burst out laughing, seeing himself gain an advantage in "effort value." He couldn't have been happier and nearly exploded in his seat.

"Work hard, work hard, he's sleeping, I can't slack off!"

"I have to take this opportunity to learn more."

"Now, most textbooks establish the Green Function method using a three-dimensional Laplace equation background. Its core content is the spatial form of Green's formula and a point-analytic representation of three-dimensional harmonic functions. The Green Function method for two-dimensional problems has similarities with the three-dimensional problems...%@@!"

The content was obviously very difficult, and even high attractiveness couldn't directly boost the intelligence of male livestock, making the whole classroom atmosphere very awkward, equivalent to a pretty girl talking to herself on the podium.

The basic knowledge of the Green Function method is double integrals and triple integrals. Ye Kaifu racked his brains, only to find he had forgotten most of it, occasionally skipping some content.

Skipping and skipping, he ended up not knowing what the teacher was talking about.

He simply gave up, dared not play with his phone in the first row, and just appreciated the teacher's beauty.

"Oh my gosh... Now I know why my boss couldn't be bothered to take this class and sent me instead."

"It's really torturous!"

Seeing pairs of bewildered eyes, heads nodding off, and some punks playing with their phones, Wang Lili stood at the blackboard, continuously ridiculing in her heart.

"This is basically a class on a bunch of pigs..."

So, she seemed to forget that she had gone through this herself. Her teacher probably viewed her as a pig too.

"Endure, endure!"

"Can't hold it, so annoying!"

Wang Lili didn't have the broad tolerance of an old professor, with a bunch of students playing with their phones and dozing off while continuing to deliver a sermon.

She wasn't pleased either. She had painstakingly prepared for the class, and they were playing down there?

Why should I? Make me preach like a nun, I can't do that...

Hmm, let's call on a few people to liven up the classroom atmosphere and wake up those who are sleeping!

Just like that!

This guy in the first row looked pretty serious; he sat in the first row from the beginning, so the probability of being a top student was quite high.

He should be able to answer the question, and it's his turn, so no one's embarrassed, and it can wake up the sleeping ones.

"This student, could you solve this problem?" Wang Lili suddenly said with a smile.

The atmosphere in the classroom suddenly became serious. "Roll call" was indeed a nuclear weapon in the classroom; almost all the sleeping students fell from paradise and quickly returned to the mortal world.

Those playing with their phones also put their phones back in their pockets...

"What? Me?" Ye Kaifu stood up, his face turning red.

He pretended to study seriously, only to be called to answer a question.

How tragic.

Really.

"Student, first consider..." Wang Lili slightly reminded him with a few more words.

"Uh, this, the Green function... two-dimensional Green function..." Ye Kaifu weakly said.

Aside from these words, he seemed to know nothing else.

He kept scratching his head and rubbing his ears, his brain spinning intensely.

Sadly, even if his head exploded, he couldn't solve this problem.

"Sigh, sit down, sit down..." Wang Lili hadn't expected the good student in the front row couldn't answer, so she had to wave her hand in dismay.

Perhaps it was that her teaching was too bad, or maybe the content was just too difficult...

However, the classroom atmosphere improved quite a bit.

After all this, everyone had straightened up in their seats, except for a few stubborn ones who were still asleep, genuinely asleep.

Especially the one on the far left of the first row, sleeping too comfortably, right? Sleeping in the first row was too influential!

"Does anyone know how to solve this problem? Just follow the method I just mentioned, using a harmonic function..." Wang Lili reiterated.

The classroom atmosphere was very awkward for a moment.

"This... the student on the far left?"

Ye Kaifu quickly tapped the slumbering Zhang Yuan, making him jump up from his seat with an "Ah."

What's going on?

Zhang Yuan opened his eyes in confusion.

A small laugh echoed through the classroom.

"The teacher asked you to solve the problem!" Sitting beside him, Ye Kaifu winked and was amused beyond measure.

Zhang Yuan blushed and scratched his head in embarrassment.

Because of continuous late-night work and excessive fatigue, he accidentally fell asleep.

"Student, can you do it?"

Although a bit displeased, Wang Lili was ready to let the student sit down after waking him up.

Everyone was an adult, responsible for their own life choices, and there was no need to overly criticize others.

Besides, this was just a course arranged by the school for various competitions, with no exams and no binding agreement...

Zhang Yuan glanced at the PPT; his slightly dazed mind started to clear. He quietly said, "It should be solved using the Green function..."

Everyone laughed. The Green function had been discussed for the entire class, and even a pig would remember these four words. Surely this guy only repeated those words after sleeping through the whole class.

Zhang Yuan paused for only two seconds, then continued, "Let v be another known harmonic function on the plane D. According to Green's formula, 0=∫∫(v∂u/∂n-u∂v/∂n)dδ. After subtracting the two equations... considering the boundary conditions..."

"￥@…%￥"

A few top students perked up their ears and vaguely understood what he was talking about.

Thinking back and forth, it seemed right and wasn't nonsense.

If someone could ramble to such a level, they'd be astonishingly impressive...

Whispering rose in the classroom.

What was happening?

A sleeping guy just obliterated them all!

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