I'm afraid I'm not interested in love

Chapter 79 Go on stage to do the questions
So a few people returned to the classroom.

What a coincidence, it was Li Lu's class in the afternoon.

In the end, he was still punished. Su Chengyi looked at Li Lu's gloomy expression.

"Put down the pens in your hands for a moment."

Li Lu first tapped the blackboard lightly, then when she saw that no one looked up, she tapped again.

"Boom!"

There was a loud noise, and the chalk dust fell.

Everyone was so frightened that they sat with their backs straightened.

"They all looked at the question on the screen."

Li Lu enlarged the question a little more on the computer, but the graphics were still slightly blurry.

She "tsk" impatiently, raised her hand and drew a new shape on the left and right sides of the blackboard.

Sometimes I really admire these teachers' ability to draw on the blackboard. The squares they draw are squares and the circles they draw are round.

After finishing the painting, she turned around and saw the eyes of her classmates following her hands, and her eyebrows suddenly furrowed.

"Let you read the question! Why are you looking at me? Is there a question on my face?"

Su Chengyi secretly laughed, took out a piece of draft paper, and copied the graphics on the blackboard onto the paper without using a ruler.

In order to avoid blocking the blackboard, Li Lu stepped down from the podium and began to patrol the classroom.

"Let's look at the questions first and sort out our thoughts. I'll ask two classmates to do it later."

As soon as she said these words, there was a sudden intake of breath in the classroom, fearing that she was the unlucky one.

Just from the complexity of this figure, you can tell that this is definitely not a question of ordinary difficulty.

Zou Lian started writing furiously as soon as the topic appeared on the blackboard, as if he was determined to win.

Chu Qingmian was conscientiously using a compass and a ruler to draw the picture. Next to her, Han Bing's face was wrinkled with worry and he was on the verge of giving up before he even started.

After Su Chengyi finished drawing, he checked the points one by one to see if they were marked correctly.

Suddenly thinking of Chen Jinzhi's injured right wrist, he turned his head.

Chen Jinzhi, who was in a daze, was obviously startled by him and looked at him in astonishment.

Su Chengyi said nothing and put the drawing paper on her desk.

Chen Jinzhi smiled and whispered:

"I can not do that."

Su Chengyi blinked and whispered:
"I'll teach you later."

"Stop whispering to each other! Do your homework!"

Li Lu knocked on the desk loudly.

Su Chengyi suppressed a smile and turned around, turning his pen and starting to read the question.

In fact, he has always felt that complex graphics is not a bad thing. Complex graphics represents an increase in known conditions to a certain extent.

At the same time, it also represents an increase in problem-solving ideas.

"In triangle ABC, M is the midpoint of side AC, and D and E are two points on the tangent of the circumcircle of triangle ABC at the point."

"Proof: ∠BCQ = ∠BAC."

Su Chengyi did not rush to make auxiliary lines, but first analyzed the basic properties of the entire figure based on the known conditions.

As I read and wrote, the known conditions given on the question stem were gradually enriched.

After this process, the problem-solving ideas are ready to emerge.

It's not that hard.

Su Chengyi came to a conclusion on this question.

If he increases the difficulty, he will subtract one or two known conditions. For example, if it is necessary to prove that MD and AB are parallel, the difficulty will rise sharply.

"Okay, you should have seen it almost, right?"

Li Lu clapped her hands, indicating that she was about to start whipping him. "No, no! I haven't finished it yet!"

Han Bing quickly waved her hands. When she raised her head, the others also shouted.

"No, no!"

Li Lu's eyes were as wide as bells, and the classroom was so quiet that you could hear a pin drop.

Whoever steps forward at this time will be a fool.

The quiet and united atmosphere was broken by a sudden voice.

"Teacher, can I go up and do it?"

Zou Lian seemed to have finally done it. He raised his hands high and his eyes were full of expectation.

As a good student who cooperated with the teacher, Li Lu certainly had no reason to refuse and nodded.

"Everyone, please be more active. Classmate Zou Lian took the lead and was the first to go. Where are the others?"

Still no response.

Geometry questions are Chu Qingmian's absolute weakness. Whether it is plane geometry or solid geometry, she always gets a headache just thinking about it.

But she can also do this question, but she just doesn't want to do it on the stage.

When the students saw Chu Qingmian who was still writing and drawing with her head down, they invariably turned their attention to Su Chengyi in the back row.

He held his chin up and looked at where he was looking. His right hand was spinning the pen in boredom, without even looking like he was going to do the questions.

Of course Li Lu also observed it, and she had no choice but to sigh helplessly.

She said that she would ask her classmates to do it. Of course, she didn't mean to ask those who didn't know how to do it in the first place.

If you don’t know how to do it, what can you do if you go up there?Isn't it a waste of self-esteem to hang it there?
Unexpectedly, the few top students in mathematics who were usually more active were so quiet. One of them almost stuffed his head into the desk.

There was only one willing classmate, so she had to order another one that would definitely do it.

"Chu Qingmian, go up and do it."

After being called by Li Lu, Chu Qingmian walked up reluctantly. In sharp contrast, Zou Lian was as confident as walking on a red carpet next to her.

Su Chengyi returned his gaze to the podium and looked at the two people writing furiously with interest.

The question requires proving that two angles are equal, so the simplest way is to prove that the two triangles where the two angles are located are similar.

Obviously, the two people on the podium had the same idea, and even the auxiliary lines were the same.

"Construct the tangent line of circle PQM through Q and intersect MP at point C'"

Chu Qingmian originally wrote well according to her own ideas. Zou Lian next to her glanced at her and suddenly said with a smile, intentionally or unintentionally:
"Hey, monitor, we both thought of going together."

Chu Qingmian was startled, took a step back, and found that the two of them were indeed using the same method.

"Hey, the teacher asked us to come up and do it. He probably wanted to see different ideas. It's a pity."

Zou Lian sighed and started writing again.

Chu Qingmian frowned and thought for a while, then turned around and took the eraser and erased all the process and auxiliary lines she had written halfway.

Su Chengyi saw this from the back row and could probably guess what happened.

Zou Lian is a man of yin and yang. He doesn't change his mind when he encounters an idea?
Chu Qingmian was already thinking about the second method just below the podium, but before she could figure it out, she was called up to the stage.

Now standing on the podium, there are two different feelings than doing calculations in private.

It was inevitable to be a little nervous when everyone was paying attention to her. Chu Qingmian took a deep breath and decided to write down the ideas in her mind first.

"Assume ∠QCB=x, and we can get it from the angle separation theorem."

Su Chengyi saw the first sentence she wrote and already guessed what she was thinking.

The idea is right, but the process is a little complicated.

Using this method, she is likely to make mistakes while thinking and writing like she is doing now.

Sure enough, halfway through the process, she made a wrong step in writing the equation, but she continued to calculate as if she was unknown.

In this way, the calculations that could have been completed long ago are written more and more, and there are so many rows that the blackboard can no longer fit.

(End of this chapter)