Chapter VIII

Wednesday night self-study, today it is Gu Lu's turn to be on duty.

The evening self-study time in the third year of high school is from 7 p.m. to 10 p.m., with a total of three self-study classes.

In the first and second years of high school, evening self-study was specifically assigned to the teachers of each subject. In addition, due to the tight teaching tasks, it is not uncommon for evening self-study to give regular lectures.

However, in the third year of high school, in order to allow students to have more time at their own disposal, evening self-study has become just a simple self-study time.

As long as you don't do anything unrelated to studying, you can spend these three hours at your disposal.

"I'm in the math office downstairs, so you can come to me if you have any problems or problems you don't know. Also, don't make small gestures, I'll come over from time to time. ”

After explaining this to the students of Class 18, Gu Lu returned to the office of the mathematics group.

I have to continue to get that academic paper after work tomorrow, so Gu Lu plans to finish the papers to be tested in the weekly test tonight.

Ten multiple-choice questions and five fill-in-the-blank questions, this is the question that Gu Lu wants to come up with.

Sitting in front of the computer, Gu Lu pondered for a few seconds, then put his fingers on the keyboard and typed down the question.

Since it is a test question specially given to key classes, the difficulty must not be the same as that of ordinary questions.

After searching in his mind, Gu Lu already had an idea.

[1. Let the complex number z,w satisfy |z|=3,(z+w:)(z:-w)=7+4i, where i is an imaginary unit, z:,w: represent the conjugate complex of z,w respectively, then the modulo of (z+2w:)(z:-2w) is ()

A.√42 B.√65.C.√71D.3…………】

[2. Let the function f(x)=sin^4(kx/10)+cos^4(kx/10), where k is a positive integer......]

[11. Knowing that f(x) is an odd function on R, f(1)=1, and for any x<0, there is f(x/(x-1))=xf(x), then the value of f(1)f(1/100)+f(1/2)f(1/99)+f(1/3)f(1/98)+......+f(1/50)f(1/51) is ______]

............

"That's it!"

Gu Lu looked at the few questions he came up with, and the corners of his mouth curled.

On the whole, Gu Lu is quite satisfied with these questions.

Gu Lu rubbed his hands, looking forward to what the students would say about these questions.

"Yes, at least there will be a four-star review. Gu Lu muttered in his heart.

He smiled and shook his head, got up and left the office, ready to go upstairs to see how the class was doing.

Coming to the door of the eighteenth class classroom, Gu Lu put his hand on the doorknob and just wanted to unscrew it in, but it seemed that he thought of something, and his hand on the doorknob was released.

Then he walked softly to the back door of the classroom and pressed his face against the small glass window at the back door.

Gu Lu finally understood why teachers in middle school had the habit of peeping through the back door window.

From this point of view, almost all the students in the class can see their every move, and no one is aware that there is a pair of eyes staring at them at this moment.

That feeling of voyeurism made Gu Lu feel very sour, and even a little happy.

To be honest, when he was in middle school, the most annoying thing for Gu Lu was the teacher's sneaky observation from the back door.

At that time, Gu Lu was caught many times by the head teacher because he brushed the math competition questions in other subjects.

But now, Gu Lu has enjoyed this state of voyeurism.

"I don't count, I live as I hate the most. Gu Lu smiled bitterly and shrugged, came to the front door and walked into the classroom.

Gu Lu went straight to the little fat man in the back row, knocked on the table, and looked at him condescendingly, "Take it out, I'll see it clearly at the back door." ”

The little fat man hesitated and took out a novel from the hole in the table and handed it to Gu Lu tremblingly.

"Come to me on weekends. ”

After saying this, Gu Lu took the novel and walked to the podium.

"I'm afraid your head teacher has told you many times, but I'm going to repeat it to you here. Your parents didn't send you here to play games and read novels. Since you choose to sit here, you should know what to do and what not to do. You have only one task now, and that is to study hard! and put everything else aside as much as possible. ”

"OK, you guys continue to study on your own. I'll sit here for a while, and just raise my hand if there's a question that needs to be answered. ”

Gu Lu moved a chair, crossed his fingers, and glanced down with a sharp gaze.

Several classmates raised their hands one after another, and Gu Lu walked over in turn to answer their questions.

“...... Here, substitute the formula after the derivative of the previous step into this equation, and change the form on both sides of the equal sign, and you can make this problem. ”

"Well, I see, thank you, teacher!"

What made Gu Lu a little puzzled was that most of the questions asked to him were girls, and the questions asked should not be difficult for students in key classes like them.

Before Gu Lu could think about it, at this time, a pair of small hands were raised again.

"Classmate Su Ling, do you have a question for me?"

Gu Lu has an impression of this little girl, Su Ling, who is the female classmate who came to shoot him with a SLR in the morning.

Su Ling tilted his head and said, "Teacher, can I ask a question before I talk about the topic." Teacher, are you good at physics?"

Physics?

Gu Lu chuckled, "It's okay, I've published two SCI papers in the field of physics, mainly in the direction of condensed matter physics and quantum physics. Uh, well, I said this you probably don't understand. You have a physics question to ask, this is no problem, show me the question. ”

"Ah, that's the question. The physics teacher is not here now, so I can only trouble you, teacher!" Su Ling pointed to a question on the test paper with the tip of his pen and spoke.

Gu Lu swept the question and raised his eyebrows, "The topic of last year's CPhO (National Physics Competition for Middle School Students) finals?"

Su Ling's eyes lit up, "Teacher, do you also know CPhO?"

Not only do I know, but I am also the first prize of CPhO for three years in a row!

Gu Lu didn't bother to pretend to be forced in front of a little girl, just smiled faintly and didn't continue to discuss this issue.

"Let's go back to this question, I've come up with a solution, I'll tell you about it, and you listen carefully. ”

"Wow, you always have an idea in such a short time!"

"No fuss. Gu Lu smiled and began to explain the question, "This question is not very difficult, but there are too many conditions given in the question, so I don't know which condition to use when doing the question." ”

"Take a look at the first question, it asks you the distance from the rod to the strike center O, this is very simple, you set the distance between the strike center position and the axis L, the horizontal external force F and the angular acceleration acting on the rear rod of the strike center β the problem is given to you, the dynamic equation of the fixed axis rotation of the rigid body has FL=1/3Ml^2β, and Ml^2β in this formula is ......"

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