Zhang Ruiyun returned to her office and immediately took out a pen and paper to calculate.
" This second question involves an exponential function. It's quite difficult…"
He hadn't been in contact with mathematics for a few years.
Even if he knew the knowledge points, he did not know where to start.
"Forget it! Send it to my university group chat!"
Zhang Ruiyun studied mathematics at the university. In his university group, the worst student was a mathematics teacher. There were some university professors, mathematics research institutes, and so on.
When Zhang Ruiyun posted this question, someone immediately popped up.
"Zhang Ruiyun, didn't you quit being a math teacher? Why did you suddenly send a question in?"
"Is it because your child encountered a problem and didn't come to ask you?”
"Is this question a little difficult?"
"Which year's final exam question? No, I know all the questions in the national college entrance examination every year, but there's no such question…"
"Zhang Ruiyun, where did you get this question?”
"Can you help introduce the person who came up with this question?”
When the students in the group saw this question, they were like hungry tigers pouncing on their food. After asking in the group, they couldn't wait to chat privately.
Zhang Ruiyun said," Don't be so agitated!”
"I mainly want to ask you guys how you did with this question. Is there any problem?"
Everyone in the group: "???"
"There's nothing wrong with this question! I roughly looked at it and it was definitely a good question!”
"I'm already asking the second question!"
"The first question is just that. The second question is the essence!”
"Yes! Indeed, this second question had the flavor of the final question of the college entrance examination!”
Zhang Ruiyun was speechless.
At this moment, even Professor Chen Jianhua, who had been lurking in the group, spoke up.
As their math teacher in school, Professor Chen Jianhua was obsessed with math, and even Qingbei had always wanted to poach him.
Although he was in his seventies and had retired, he was still very influential in the mathematics world.
Chen Jianhua said," This question is not bad.”
Zhang Ruiyun was speechless.
"Teacher Chen, why are you here too? This, this, this…"
Chen Jianhua joked," Good question. Why don't you let an old man like me have a look?”
Zhang Ruiyun was so frightened that her entire body was trembling." Teacher Chen, what are you talking about?!" I'm just afraid that the questions are not good, that I'll make a mistake, and make a mistake!”
He knew very well that no matter how big the matter in the group was, it would not attract the attention of this old professor. However, today, as soon as this question was posted in the group, the old professor popped up.
A student in the group said," Teacher Chen, didn't you say that you're retiring and won't care about mathematics anymore?”
Chen Jianhua said," I'm itching to see a good question.”
It was enough to show how much importance Chen Jianhua placed on this question.
This was something that Zhu Ruiyun had never expected!
"Ruiyun! The person who set this question must have participated in the college entrance examination, right?”
Many people echoed," It must be the teachers from the college entrance examination's paper distribution team!”
"Even the teacher who produced the test paper spent a lot of time on this question!”
"At least a week!"
"A conservative estimate! Anyway, give it to me. I didn't expect it to be so ingenious!”
Zhang Ruiyun pursed her lips and looked at the discussion on the phone. She was even more uncertain.
"Teacher Zhao wouldn't have taken out his own questions to show off before. The reason why he took them out this time is because he was angry.”
"So Xu Heng couldn't have seen the questions in advance!”
"But this doesn't make sense! It's too mystical!"
"Even if he started thinking after seeing the question, it hasn't even been fifteen minutes. How could he think of the second question?”
"And his skill is so high!"
Just as Zhang Ruiyun was feeling puzzled, someone in the group tagged him and asked," What's the answer? b minus a divided by 2, right?”
How could Zhang Ruiyun know if it was right or not?
Goosebumps rose all over his body. He stood up abruptly and rushed out of the office.
When he arrived at Class 30, he was about to knock on the door when he saw Wei Minghai writing the solution on the blackboard.
Explanation:
if| p1-p2|>log (3) 2, discuss separately
(1) When p1-p2>log (3) 2, f1 (x)…
……
Because f (a)=f (b), so…
……
The length of the monotonously increasing interval of f (x) on the interval [a, b] and b-p1 {(p1 p2-log (3) 2)/2}-p2=b-(p1 p2 log (3) 2)/2=b-(a b)2=(b-a)/2
(2)When p2-p1>log? 2 o'clock…
……
The final result was still (b-a)/2!
They were densely packed and filled the entire blackboard!
Rumble!
It was as if he had been struck by lightning, as if an electric current had been poured down, causing Zhang Ruiyun to be dumbfounded.
Wei Minghai said,"In summary, the length of the monotone interval of f (x) on the interval [a, b] is the difference of 2/b-a. Teacher Xu, is my answer correct?"
Xu Heng nodded slowly.
Rumble! Rumble!
Zhang Ruiyun's legs went limp and she could barely stand.
As a student, Wei Minghai actually gave the correct answer in such a short time!
It was about the same time as his senior mathematics classmates in the group!
"Genius!"
"An absolute genius!"
"This Teacher Xu, he's godly…"
Just as Zhang Ruiyun admitted that the answer was correct in the group, and the students in the group were discussing the complicated solution to this question...
Xu Heng said to the class," This question doesn't have to be so complicated. Wei Minghai, let me remind you about the absolute value function.”
Her words woke him up from his dream!
Wei Minghai's eyes lit up, and he immediately erased his previous thoughts.
"Shua! Shua! Shua! Shua…"
This book comes from：m.funovel.com。