Chapter 8

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

The evening self-study time for senior high school students is from 7pm to 10pm, with a total of three self-study classes.

In the first and second years of high school, evening self-study was specifically assigned to teachers of each subject. And due to the tight teaching workload, it often happened that evening self-study was used to teach the main lesson.

But when entering the senior year of high school, in order to allow students to have more time at their own disposal, evening self-study becomes just a pure self-study time.

As long as you don't do anything unrelated to study, these three hours are at your disposal.

"I'm in the math team's office downstairs. If you encounter anything, or if you don't know a question, you can come to me. Also, don't do any tricks. I will come over and hang out from time to time."

After explaining this to his classmates in Class 18, Gu Lu returned to the math department office.

He will continue working on the academic paper after get off work tomorrow, so Gu Lu plans to complete the papers for the weekly test during this time tonight.

Ten multiple-choice questions and five fill-in-the-blank questions, these are the questions Gu Lu will ask.

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

Since the test questions are specially given to key classes, the difficulty level must not be the same as ordinary questions.

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

[1. Suppose the complex numbers z and w satisfy |z|=3, (zw:)(z:-w)=74i, where i is the imaginary unit, z:, w: respectively represent the conjugate complex numbers of z and w, then

The modulus of (z2w:)(z:-2w) is ()

A.√42 B.√65.C.√71D.3…………]

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

[11. It is known that f(x) is an odd function on R, f(1)=1, and for any x<0, f(x/(x-1))=xf(x), then f

(1)f(1/100)f(1/2)f(1/99)f(1/3)f(1/98)……The value of f(1/50)f(1/51) is

______]

…………

"Done!"

Gu Lu looked at the questions he asked and raised the corner of his mouth.

Overall, Gu Lu was quite satisfied with these questions.

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

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

He immediately smiled and shook his head, stood up and left the office, preparing to go upstairs to see the current situation in the class.

When he came to the door of Class 18 classroom, Gu Lu put his hand on the door handle and was about to turn it open and go in, but he seemed to have thought of something and loosened his grip on the door handle.

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

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

From this perspective, almost every move of all the students in the class could be seen, and no one noticed that there was a pair of eyes staring at them at this moment.

The feeling of being voyeuristically taken for granted made Gu Lu feel very sad, and he even enjoyed it a little bit.

To be honest, the thing that Gu Lu hated most when he was in middle school was the teacher secretly observing from the back door.

At that time, Gu Lu was caught by his class teacher many times for doing math competition questions during classes in other subjects.

But now, Gu Lu has enjoyed this voyeuristic state.

"Do you think I am living in the way I hate the most?" Gu Lu smiled wryly and shrugged, walked to the front door and walked into the classroom.

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

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

"Come to me and ask for it during the weekend."

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

"I'm afraid your head teacher has told you this many times, but I still have 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 should be done and what should not be done. You have only one task now, which is to study hard! Try to put other things aside as much as possible."

"OK, you continue your self-study. I'll sit here for a while. If you have any questions that need to be answered, just raise your hand."

Gu Lu moved a chair, crossed his fingers, and scanned the bottom with sharp eyes.

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

"...Here, substitute the formula derived from the derivation in the previous step into this calculation, change the forms on both sides of the equal sign, and you can solve this problem."

"Well, I understand. Thank you, teacher!"

What makes Gu Lu a little puzzled is that most of the questions asked by him are girls, and the questions asked should not be called difficult for students in key classes like them.

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

"Classmate Su Ling, you also have a question to ask me? Tell me, which question is it?" Gu Lu said with a smile.

Gu Lu had an impression of this little girl. Su Ling was the female classmate who came to take pictures of him with a SLR in the morning.

Su Ling raised her head and said, "Teacher, before I talk about the topic, can I ask a question first? Teacher, are your physics good?"

physics?

Gu Lu chuckled lightly, "It's not bad. I have published two SCI papers in the field of physics, mainly researching condensed matter physics and quantum physics. Uh, okay, you may not understand what I say. Do you have

You want to ask a physics question, that’s no problem, just give me the question to take a look at.”

"Hey, this is the question. The physics teacher is not here right now, so I can only trouble you, teacher!" Su Ling pointed at a question on the test paper with the tip of her pen and spoke.

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

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

Not only did I know it, but I was also the first prize winner of CPhO for three consecutive years!

Gu Lu was too lazy to show off in front of a little girl, so he just smiled lightly and did not discuss the issue any further.

"Let's go back to this question. I have already figured out the solution and will explain it to you. Please listen carefully."

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

"Nothing surprising." 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.

"

"Look at the first question. It asks you about the distance from the rod to the center of impact O. This is very simple. You set the distance from the center of impact to the axis of rotation as L . The horizontal external force F and the angular acceleration β of the rod acting on the center of impact are all given.

You know, the dynamic equation that is substituted into the fixed-axis rotation of a rigid body is FL=1/3Ml^2β. In this formula, Ml^2β is..."

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Chapter completed!