Xueba: The knowledge I taught will be returned by crit

How many stars is the difficulty of this series question?

For science students in their third year of high school, it’s definitely five stars (five stars out of the stars).

This kind of series of questions is one of the most difficult types of questions in the high school examination paper.

Even for a college student, solving this topic requires some effort.

Even, the vast majority of ordinary undergraduate college students do not do this series problem, or only do the first question.

Because this kind of question is reserved for those students who took the Qingbei and 211/985 universities, it is difficult for ordinary students to get full marks.

“Of course.” Gu Bai smiled confidently and answered the only audience in the live broadcast room.

Although Gu Bai is not a student of a prestigious university, but… At the end of the college entrance examination, he specifically inquired about this topic.

So for this topic, he has a good idea.

Habitually turned the black signature pen in his hand, Gu Bai brushed on the scratch paper, and explained in his mouth: “This is a typical series problem.” ”

“From the known conditions given in the title, we can conclude two conclusions: (1) when n = 1, a1 = a2, which corresponds to An2; (2) Suppose that n=k, (k=2) holds the conclusion, so we can get Ak2, so when n=k+1….”

“…. So when n = k+1, the conclusion An2 still holds. So for everything n∈N, An2 holds. ”

Almost less than a minute.

Gu Bai asked for the first small question on this topic.

At this time, Gu Bai did not continue to explain in a hurry, but asked the audience in the live broadcast room: “First small question, do you understand?” ”

“Understood, understood, the anchor continues!”

Suddenly, the ID named ‘The Cat in the Corner’ in Gu Bai’s live broadcast room published a barrage.

“Hmm.” Gu Bai snorted and continued.

【…. It can be found that the sequence An is monotonically decreasing. 】

【…… When n=1 is, S1=32+43, when n=2 is, Sn=3+a2+a3+… an3+[2+（14）]+….. So when a=3 is, Sn2n+4/3].

For the explanation of the two small questions behind this question, Gu Bai’s speed slowed down.

He was afraid that the other party would not understand.

However, Gu Bai once again underestimated the 20% comprehension blessing of systematic teaching.

Comprehension, also known as comprehension, is one of the most important skills in learning mathematics.

In class, the math teacher will a topic that some students can understand at once, and some students have to repeat it several times, and the reason for this is the gap in comprehension ability.

Gu Bai didn’t know how strong an ordinary student could become with the blessing of 20% of his comprehension.

But… The facts show that Li Sisi can understand the Olympiad topics explained by Gu Bai, and the audience in this live broadcast room in front of him can also understand the most difficult number series module in the college entrance examination.

Of course, Gu Bai knows that this also has a certain premise, and this premise is that you must have a certain foundation.

Can’t a guy who doesn’t even know log, cos, you let him understand trigonometric problems, right?

Isn’t this a ripping calf in broad daylight?

Gu Bai is not a god, he is just a small hanging wall.

“666, 666.”

“I really didn’t expect the anchor to have two brushes, I actually understood it at once, and it didn’t feel very hard!”

“To know this kind of topic, our math teacher explained, it is difficult for me to understand.”

Suddenly, 3 barrages crossed.

These 3 barrages were all issued by this ID named ‘Cat in the Corner’.

Looking at the barrage, Gu Bai smiled.

6 what 6, isn’t this a basic operation?

I’m hanging on the wall, following me, and it’s absolutely no problem to get into a prestigious university.

Of course, he did not say this sentence.

At the same time, Gu Bai could feel that this audience was probably already hung up and curious.

So… The first fan, there is.

Sure enough.

In the follow-up to Gu Bai’s live broadcast, the audience with the ID ‘Cat in the Corner’ has not left, and it has always been her asking Gu Bai questions.

He or she obviously became the first loyal fan of Gu Bai’s live broadcast room.

………………………………………………

Fat Province, Yangcheng No. 1 High School.

“I understand again, I understand again.”

“This anchor feels so good, I can understand the topics explained.”

A young girl in a gray and white school uniform with a ponytail, she clenched her fists a little excited.

Liu Yanyan looked up at the big words ‘103 days before the college entrance examination’ on the podium, and a touch of impulse suddenly welled up in her heart.

Sprint a wave of 985 universities!

Liu Yanyan’s grades are medium in the class, and she plays normally in one exam, and she may not be able to get one of them if she does not play well.

And the subject that gave her the most headache was mathematics.

And just after hearing Gu Bai explain a set of test papers in the live broadcast room, she felt that it was not so difficult, and even… And it’s easy.

This excites her a little because her worst subject is math.

If she can score 120-130 in math, she has absolute confidence in sprinting to 985/211 college.

“Xiaoyan, don’t play Douyin anymore, there are only more than 100 days left before the college entrance examination.”

On the side, Wang Na’s voice at the same table urged the voice.

“I’m not playing fighting, I’m learning.” Liu Yanyan held up her hair and explained.

There are not many days before the college entrance examination, and now every student in the class is studying hard, of course, they are also urging each other.

As Liu Yanyan’s tablemate, Wang Na saw Liu Yanyan playing with her mobile phone, so she kindly reminded her.

“Study, obviously watching Douyin live broadcast.” Wang Na said hehe.

“Really learning.”

Liu Yanyan handed her mobile phone to the side of the same table and explained: “This live broadcast room is teaching ‘mathematics’, and the word ‘country’ you asked him just now was asked to him.” ”

“Live math teaching?” Wang Na was a little suspicious.

“That’s right. I can’t understand what our math teacher said, but I can understand everything this anchor says, and I remember it very deeply. ”

After speaking, Liu Yanyan added: “Really, I also understood the most difficult number series problem again. ”

Cut ~~

Wang Na rolled her eyes, completely unconvinced.

“Really, what I said is true.” Liu Yanyan explained again.

Wang Na shook her head and stopped reasoning, thinking in her heart: “If this anchor can improve your grades, my Wang ‘surname’ will be written backwards.” ”

Wang Na doesn’t think that live teaching is as good as their teachers.

And… Just now she glanced at it, this anchor didn’t even have a decent lecture room, and she looked like a young man, how could she teach well.

Unless… To hell with it.

May Day reading is happy! Charge 100 and get 500 VIP bonds!

immediately preemptive (Event Period: April 29 to May 3)