Xueba: I missed one exam, and I won the first place in the school

Teacher, is my speech okay?

“It is known that the eccentricity of the ellipse x2/a2 plus y2/b2 is equal to 1 (a is greater than b and greater than 0). Find the maximum and minimum values ​​of the vector PF1 multiplied by PF2.”

After Jiang Feng finished writing, he raised the corner of his mouth in embarrassment.

Put this topic in my class, I’m afraid I can do it if I haven’t learned ellipse.

I’m actually stumped here…

“This question is probably the third most difficult question on the test paper. Do you have any ideas? You can sit down and ask it directly.”

The students below sat quietly without speaking.

Wu Zhipeng covered his face in shame.

No one will believe me when I say it out, the whole class scored 0 for this question…

He doesn’t even know how to speak!

Standing on the stage, it’s like performing a one-man show!

It’s completely playing the piano against the cow.

Jiang Feng: “…”

“Okay, if you have no ideas, let’s take a look at the evolved topic.”

Wu Zhipeng shook his head slightly, showing a disappointed face.

It’s useless, I used this method myself.

Four or five questions were changed, but they still didn’t help.

Sure enough, “It’s hard for a clever woman to cook without rice”, “It’s hard for Lu Ban to do a dead wood”… Class 2 of the third year of high school, as strong as a river, can’t be saved!

Jiang Feng quickly wrote another topic next to the original topic.

“It is known that x belongs to the value domain of… the function….”

“Is there anyone who knows this topic?”

Everyone’s eyes lit up!

“I will!”

“I will!”

“I can do it too!”

“This topic is too simple!”

Jiang Feng: “……”

“It can be seen that everyone has potential.”

Hiss——

Hearing such a high evaluation and recognition, the students all cheered for themselves in their hearts.Big mouth!

I am me, different fireworks!

There was excitement in their eyes, and they wanted to stand up and prove themselves more and more!

Wu Zhipeng was taken aback!

Very busy stretching his neck to look at the blackboard!

I have led the class for two years, and this is the first time I have seen such a scene since the first monthly exam in the first year of high school!

The confident and lively children are back again? Think you can do it again?

When the topic of evolution on the blackboard came into view, he couldn’t help but frown!

Surprised!

Can this topic evolve like this?

Simplification is simplification, and the basics are the basics, but it’s better to write 1 plus 1!

This… is not right!

No, no, no, no!

He looked at the original title again, and suddenly his eyes lit up!

Jiang Feng omitted all the distractions from the original topic and the tedious analysis process, leaving the last step that is clear at a glance!

The answers to the two questions are actually the same!

It is both it and it is also it!

Wonderful, as the saying goes, from the shallow to the deep, it is easy, and from the deep to the shallow, it is difficult.

Jiang Feng immediately grasped the meaning of the title, um no, the true meaning!

The word “service” in capital letters in his heart is slowly being completed.

Jiang Feng called a boy in the back row, “Tell me about it.”

The boy stood up excitedly, and answered the question three times, five times and two times.

“Pretty, very neat.”

Jiang Feng praised again, and pointed to the original question, “You already know how to do this question.”

The boy was dumbfounded, and spread his hands, “I can’t.”

Jiang Feng frowned slightly.

The comprehension here is still weak, and I need some advice.

“What about the others, do you have any ideas now?”

Yan Xue, who had been staring at the blackboard and thinking seriously, raised her hand.

Jiang Feng showed a satisfied smile, “Please tell me.”

“Write two vectors according to the coordinates of P, F1, and F2, and then multiply them to get the expression about x, y… Then combine the relationship between x and y, that is, the expression of the ellipse, and eliminate one unknown, and finally get the new expression…”

Yan Xue’s eyes were focused, and her face was shocked!

“Damn it!”

The sweet, clean and soft Chinese quintessence reverberates in the classroom!

The whole class stared at the blackboard, and was also surprised!

The finally obtained expression for the required value range is Mr. Jiang Feng’s evolved topic!

No wonder the teacher gave us this problem.

It’s no wonder that we’ve already met!

It’s a pity that we are still wondering what the relationship between the two topics is!

Jiang Feng smiled and nodded, “It’s great, let’s give this…”

“Yan Xue.” Yan Xue blushed slightly.

“Give a round of applause to Squad Leader Yan Xue.”

Crash!

applause.

A boy in the middle of the classroom stood up weakly, raised his hand and said in a daze, “Teacher, I am the monitor…”

The whole class: “???”

Jiang Feng: “???”

Wu Zhipeng: “You are the squad leader? Who said that?”

Chen Li: “…”

“You just said it at the class meeting a few days ago…”

Wu Zhipeng looked at the whole class and asked in surprise, “Did I say that?”

The students spread their hands, “No.”

So what did you say? Now that Mr. Jiang Feng has re-employed, is this a contradiction?

No contradiction!

Chen Li: “……”

Quickly hide her face and sit down.

I’m sorry everyone, but I’m not deeply involved in the world!

“So these topics are disguised as ellipses and vectors to confuse everyone.”

Section 122

“After careful analysis, it is the simple function problem we are most familiar with.”

“Everyone do more exercises. Doing this kind of problem in the future will be as easy as drinking water.”

Everyone nodded, with a confident look on their faces.

We believe it! We believe so much!

Wu Zhipeng slowed down his rapid breathing.

He couldn’t figure out how to explain the topic, and Jiang Feng gave him the most perfect answer within a minute.

Explain the topic thoroughly, understand the students, and convince him!

Jiang Feng is a genius at teaching!

Jiang Feng’s eyes fell on the test paper again.

What I just talked about was the third most difficult question from the bottom. No matter how difficult it is, only the last two questions are left.

“Let’s take a look…Forget it.”

He raised his head and said solemnly, “It will definitely be beneficial for you to remember my words. From now on, the last two questions of the math test paper will not take more than five minutes.”

“!!!”

Everyone was shocked!

“Teacher, isn’t this asking too much?”

“Yeah, what topics can you do in five minutes?”

“Those bullies in the intensive class can’t do it either.”

Yan Xue turned her head and looked back, “What the teacher said is not to give up quickly, spend more time to ensure the correct rate in front!”

Jiang Feng cast a knowing look, and said to the whole class: “Only the squad leader will follow the lead.”

The thinking of these difficult problems is a bit complicated. Even if it is divided into steps, and each step is simplified to the extreme, it will be a lot of difficulties for the “seniors” in front of them.

Everyone breathed a sigh of relief, showing sincerity.

The students understand!

Wu Zhipeng has finished writing the word “serve” in his heart, and gave it a thumbs up again!

Jiang Feng perfectly understands teaching students in accordance with their aptitude!

…

“That’s all for this class, let’s get ready to end get out of class.”

After Jiang Feng finished all the preparatory content, there were still five minutes left before get out of class ended.

He stepped off the podium, leaned next to Wu Zhipeng, bent overSaid: “Teacher, is what I said okay?”