Chapter 166

It's November.

Autumn is high and cool, and the weather in Yanjing is slightly cool.

Gu Lu put on a windbreaker outside, stepped on the leaves falling from the trees on the side of the road, and came to the classroom.

At present, the first half of the freshman year has passed the halfway point, and the students of the Department of Mathematics are gradually adapting to the rhythm of university life.

For the students of Yan University, university life may not be much easier than high school.

Yan University brings together outstanding students from all over the country, and at the same time, it means that the competition is more brutal and fierce.

No one dares to slack off easily.

Therefore, the library has become the most frequented place for their dormitories and classrooms.

Staying up late until 12 o'clock in the evening has gradually become a norm.

At five o'clock in the morning, they can often watch the night view of Yanda.

In the early morning, the shore of Weiming Lake is always occupied by a group of students who memorize words.

Even on the campus benches, in the quiet café, you can see a couple holding a book and reading.

In Yanda, the learning atmosphere is terrible.

I'm afraid that just let one come over, and under the infection of this atmosphere, I will be eager to take out a book and read it on the spot.

There are many ways to spend a four-year college career.

The students of Yan University choose to enrich themselves with learning.

Because...... Learning makes them happy!

In their eyes, learning is not a boring thing.

Rather, it's like leveling up to fight monsters.

There is a refreshing feeling of step-by-step upgrading and self-breakthrough.

In particular, exams and competitions from time to time give them a sense of accomplishment from their studies.

In the words of Bi Qi, it is the most wonderful feeling he has ever felt in his life.

This feeling, which he indulges in.

It's like sucking a DU product, and I can't extricate myself.

…………

After the class was over, Bi Qi held a stack of homework and followed Gu Lu back to the office.

In universities, there are generally no classes to represent this position.

As for the sending and receiving of homework, it is naturally the sole responsibility of the hard-working class president.

"Teacher, I've read all the book lists you gave me for the first course of treatment. Putting down his homework, Bi Qi said to Gu Lu.

"It took a month?" Gu Lu raised his eyebrows and counted the days, "It's been a little long!"

Bi Qi scratched his head and smiled, "There are a lot of classes in the freshman year, so it's not good to squeeze time." ”

Gu Lu didn't say much, tore off half of the A4 paper, and wrote the titles of a few books on it, "These are the five books in the second stage, after reading these books, the knowledge reserve stage in the early stage is enough." The following can be practiced with real questions, starting with the most basic and simple ones. ”

Bi Qi nodded heavily and carefully accepted the note, "Teacher, I know." ”

Then, Bi Qi did not leave in a hurry, but stood in front of Gu Lu, looking hesitant.

Gu Lu shook his head and smiled, looking up at Bi Qi, "Say what you want to say." ”

Bi Qi clenched his fists, "Teacher, I want to apply for exemption!"

The so-called exemption refers to the approval of not attending the usual lectures.

But exemption from listening does not mean exemption from study.

For example, the usual homework, practical links, stage assessments and final exams should still be attended as usual.

"Exemption?" Gu Lu was surprised for a moment, then glanced at Bi Qi up and down, and asked with a smile, "Do you want to apply for my exemption from this course alone, or ...... All the courses?"

"All, math majors. Bizzie replied.

In the freshman year, there are three major courses in mathematics, namely advanced algebra, numeracy, and solutions.

Bi Qi now wants to apply for exemption from all three courses in one go.

"What about the other courses?" Gu Lu asked.

Bi Qi replied, "The school stipulates that applications for exemption from public politics courses, physical education courses, public foreign language courses and public elective courses will not be approved. ”

Well, it turns out that the other courses are not that Bizzie doesn't want to apply for exemption, but that the school doesn't allow it.

Gu Lu is really unclear about this provision.

When he was in college at that time, Gu Lu did not apply for exemption, but applied for a lot of exemptions.

Right...... It's the kind of exemption that you don't even need to take exams.

Gu Lu looked at Bi Qi with a smile, "You should know that if you want to successfully apply for exemption, you have to go through my assessment?"

Hearing waiver is not something that can be agreed to by just one person.

In the rules of Yan University, there are two necessary conditions for applying for exemption from hearing.

First, it is necessary to get the assessment of the teacher and successfully pass.

Second, in the final examination of the course, you must score 85 points or above, otherwise, it will be treated as a failure.

And Biqi is facing the first test.

Facing Gu Lu's smiling gaze, Bi Qi swallowed his saliva and subconsciously took a few steps back.

With Bi Qi's understanding of Gu Lu, the difficulty of Gu Lu's assessment will definitely not be low.

Bi Qi encouraged himself, took a deep breath, and nodded with a firm gaze, "Teacher, I'm ready for the challenge!"

"Are you really ready?" said Gu Lu with a smile.

In Bi Qi's eyes, the smile on Gu Lu's face had a breathtaking aura.

Bi Qi shrunk his neck, and pointed out the door with trembling fingers, "Teacher, can I go to the toilet before the assessment." ”

"Go ahead. Gu Lu waved his hand.

In less than a minute, Bi Qi pushed the door and walked in, standing in front of Gu Lu.

Gu Lu handed Bi Qi an A4 paper with a question written on it, crossed his fingers, and said, "There are five questions on it, do three correctly, and I will agree to your application for exemption." ”

"If you don't get it right, then go back and continue with the lesson. ”

After speaking, Gu Lu pointed to the small conference table placed in the center of the office and said, "Go over there and do it." As for the time limit, it's until I go to lunch. ”

It's ten o'clock.

Gu Lu usually goes to eat at about twelve o'clock.

The time left for Bizzy was only two hours.

Two hours, three questions, sounds simple, but Bizzie doesn't think so at all.

According to Mr. Gu's temperament, Bi Qi knew that none of the five questions given to him by Mr. Gu could be easily solved.

He must be 200 percent vigilant and take it seriously.

Holding the A4 paper with five questions written on it, taking a carbon pen and a stack of scratch paper handed to him by Gu Lu, Bi Qi came to the conference table and sat down at random.

Then put on the headphones, lie down on the table, and fully enter the state of answering the question.

He glanced at the title first.

Question 1: [Known elliptical cylindrical surface S.

r(u，v)={au，v}，-π≤u≤π，﹣∞≤v≤＋∞

(1): Find the equation for any geodesic on S.

(2): Let a=b, take p=(a,0,0), Q=r(u,v)={au0,v0},-π≤u0≤π,-∞≤v0≤+∞, and write the shortest curve equation connecting P and Q points on S. 】

Question 2: [Derive the calculation format of the conjugate gradient method for solving systems of linear equations, and prove that the format converges after finite step iterations.] 】

Question 3: [Let f(x) be second-order derivable on [0,1], and f(0)=f(1)=0, min(0≤x≤1)f(x)=-1.

Proof: The existence of η∈(0,1) such that f(η) ≥8. 】

Question 4: ......

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