Xueba: The knowledge I teach, critical hits are returned

How difficult is this number series question?

For a senior high school science student, it is definitely five stars (out of five).

This type of number series question is one of the most difficult types of questions in the college entrance examination.

Even for a college student, it takes some effort to solve this question.

In fact, most ordinary undergraduate students cannot solve this number series question, or can only solve question (1).

Because this type of question is reserved for students who are admitted to Tsinghua University, Peking University, or 211/985 universities. It is difficult for ordinary students to get full marks.

"Of course."Gu Bai smiled confidently and answered the only viewer in the live broadcast room.

Although Gu Bai is not a student from a famous university,...When the college entrance examination was over, he specifically looked up this question.

So he was confident about this question.

He habitually turned the black signature pen in his hand and wrote on the draft paper quickly, explaining:"This is a typical number series question."

"From the known conditions given in the question, we can draw two conclusions: ① When n=1, a1=a2, which meets An2; ② Assuming n=k, (k=2), the conclusion is valid, so we can get Ak2, so when n=k+1...."

"....Therefore, when n=k+1, conclusion An2 still holds. So for all n∈N, An2 holds."

In less than a minute,

Gu Bai solved the first question of this problem.

At this time, Gu Bai did not continue to explain in a hurry, but asked the audience in the live broadcast room:"The first question, do you understand?"

"Got it, got it, keep going!"

Suddenly, in Gu Bai's live broadcast room, the ID named 'Cat in the Corner' posted a comment

""Hmm." Gu Bai hummed and continued.

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

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

Gu Bai slowed down his explanation of the two questions after this problem.

He was afraid that the other party would not understand.

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

Comprehension, also known as comprehension ability, is the most important skill in learning mathematics.

In class, the math teacher explained a question to some students in one go, while others had to go through it several times. The reason for this was the difference in comprehension ability.

Gu Bai didn't know how strong ordinary students could become with the 20% comprehension boost.

But...The fact is that Li Sisi can understand the math problems explained by Gu Bai, and the audience in the live broadcast room 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 have to have a certain foundation.

You can't expect a guy who doesn't even know log and cos to understand trigonometric function problems?

Isn't this bullshit in broad daylight?

Gu Bai is not a god, he is just a little wall hanging

"666, 666"

"I didn't expect that you, the host, are so good at what you say. I understood it immediately and it didn't seem difficult at all!"

"You know, even our math teacher can hardly understand this kind of question."

Suddenly, three comments flashed by.

All three comments were posted by the ID"Cat in the Corner".

Looking at the comments, Gu Bai smiled.

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

I'm hanging on the wall, follow me, and you will definitely have no problem getting into a prestigious university.

Of course, he didn't say this.

At the same time, Gu Bai could feel that the audience's curiosity had probably been aroused.

So...The first fan, there is one.

As expected.

In the subsequent live broadcasts of Gu Bai, the viewer with the ID"Cat in the Corner" has never left and has always been the one asking questions to Gu Bai.

He (she) has obviously become the first loyal fan of Gu Bai's live broadcast room......................................................

Fatty Province, Yangcheng No. 1 High School

"I understand again, I understand again"

"This anchor is so good, I can understand all the questions he explains."

A young girl in a gray and white school uniform and a ponytail clenched her fists in excitement.

Liu Yanyan looked up at the big words"103 days left before the college entrance examination" on the podium, and suddenly an impulse surged in her heart.

Sprint for a 985 university!

Liu Yanyan's grades are average in the class. If she performs normally, she will get into a top university, but if she performs poorly, she may not get into any of them.

The subject that gives her the most headache is mathematics.

After listening to Gu Bai's explanation of a set of test papers in the live broadcast room just now, she felt that it was not that difficult, even...It was easy.

This made her a little excited because her worst subject was math.

If she could get 120-130 in math, she would definitely have the confidence to get into a 985/211 university.

"Xiaoyan, stop playing Douyin. There are only 100 days left before the college entrance examination."

Alongside, my deskmate Wang Na urged

"I'm not playing Douyin, I'm studying." Liu Yanyan adjusted her hair and explained.

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

As Liu Yanyan's deskmate, Wang Na saw Liu Yanyan playing with her phone, so she kindly reminded her.

"Studying, obviously watching Douyin live broadcast."Wang Na laughed and said

"Really learning."

Liu Yanyan handed the phone to her deskmate and explained:"This live broadcast room is teaching 'math'. The word 'country' you asked him just now was his."

"Live math teaching?"Wang Na was a little skeptical

"That's right. He explains it very well. I don't understand what our math teacher says, but I can understand everything this anchor says, and I remember it very clearly."

After saying that, Liu Yanyan added:"Really, I also understood the most difficult number series questions after listening to them once."

Tsk~~

Wang Na rolled her eyes, totally unconvinced

"Really, I'm telling the truth." Liu Yanyan explained again.

Wang Na shook her head and ignored her, thinking in her heart:"If this anchor can improve your grades, I will write my last name backwards."

Wang Na didn't think that live teaching was as good as their teacher.

And...She had just taken a quick look and saw that the anchor didn't even have a decent lecture room. He looked like a young man, so how could he teach well

?...Damn it!

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