I really just want to be a scholar

Chapter 3 The realm of learning gods is crushed!
As soon as this remark came out, the female students in the class looked at Qin Ke with a different color. No matter whether Qin Ke and Ning Qingyun had any ambiguity, it would be a shame to dare to stand up and defend the female classmate like this. A performance of a hero!

Even Ning Qingyun looked up at Qin Ke in surprise. This guy... actually speaks out for him?

A little bit of emotion rose in her heart unconsciously.

Girls don't know Qin Ke's true thoughts. He has been looking for opportunities to complete new functions and missions. How can such a good opportunity be missed?

He quickly calculated in his mind that there are a total of 50 students in the class, because it is a science class, there are 38 boys and only 12 girls.

If you use map cannons indiscriminately to pretend to be aggressive, although you can complete the task, but you are too brain-dead, you may be killed and completely isolated in the class. Why don't you use this opportunity to support the school committee and specifically target the boys? Woolen cloth!

Qin Keyi said with a stern voice and awe-inspiring righteousness: "The school committee has a noble character and doesn't want to argue with you. I can't see it. As boys in the science class, you can't even figure out such a simple question. How dare you think about it?" Laughing at others? Why don’t you go back and retake the abacus and mental arithmetic course in elementary school!”

The effect of this wave of map cannons in inciting hatred is overwhelming. It is like a single stone stirring up a thousand waves, and the boys are immediately dissatisfied.

Except for a few boys who usually play ball with Qin Ke and have a good relationship with him, the rest of the boys gritted their teeth and shouted. After all, they are all new classmates after the division of science in the second year of high school. They don't have much friendship with Qin Ke, and Seeing him go to class every day and sleep like he gave up his treatment, he felt even more contemptuous, so he was naturally impolite when he spoke.

"Qin Ke, Blindly became amazing when answering a question? Most likely, he read this question somewhere!"

"That's right, you really dare to say anything for your girlfriend!"

"I think you are at the level of a primary school student. Who handed in blank papers and got zero points in the last two monthly exams?"

"I don't believe that this guy did it himself. It must be Ning Qingyun who did the right thing, and then it will be blamed on him!"

Mathematics teacher Zheng Jianzhou patted the podium and shouted in a deep voice, "Why are you so noisy? Think this is a vegetable market!"

The authority of teachers in private high schools is still very heavy, let alone the always serious Lao Zheng?When the students saw him put on a straight face, they all realized that the disturbance was too much and exceeded Lao Zheng's bottom line, so they didn't dare to say anything again.

Zheng Jianzhou looked at Qin Ke, and thought to himself that if this kid can really figure out the question just now in 3 minutes, he has passed the first level of selection he set, and he has to try his potential again!However, seeing Qin Ke's lazy and idle appearance, he was afraid that this kid would lie down and sleep if he said something like he usually did, so he deliberately said with a cold face: "Qin Ke, you think you have a strong thinking ability, right? Just ask a question, you are allowed to use a pen, but you are limited to do it within 3 minutes, if you can’t do it, you will be fined to wipe the blackboard for a week, and you are not allowed to sleep in class, do you dare to agree?”

The coercion of Old Zheng's stern face is uncomfortable, but Qin Ke's grandfather is more rigid and serious than Old Zheng, and Qin Ke has long been used to this level of "death stare".

What's more, from time to time, the system next to my ear heard the sound of "Ding! Because the boys' emotions fluctuated violently, the host gained double 74 hatred points! The experience value of the god of learning +74..." prompts directly pulled Qin Ke's mood value to MAX, he shrugged indifferently:

"Okay, as long as it's within the scope of high school, even if it's in the third year of high school, teacher, you can give it whatever you want! But let's talk about it, Teacher Zheng, if I can answer it within 3 minutes, you have to let those men who muttered strange things just now The students apologized to the school committee together."

"Yes!" Zheng Jianzhou became a little annoyed when he saw his expression. He opened his lesson plan notebook, randomly chose a super-syllabus topic that he planned to use for the next monthly exam, and wrote it on the blackboard.

“已知等比数列{an}的公比q大于1，且a3＋a4＋a5＝28，a4＋2是a3，a5的等差中项。数列{bn}满足b1＝1，数列{(bn＋1－bn)an}的前n项和为2n^2＋n，求数列{bn}的通项公式。”

The students in the audience were all carefully reading the topic, and even Ning Qingyun frowned slightly.

This question is about the sum of series of numbers. According to the progress of the textbook, it should be a knowledge point that will only appear in the mathematics compulsory 5 textbook. It will be covered in about two months, but Yingyuan Private High School has always encouraged students to preview self-study in advance. There will also be a few such super-level questions for pulling points.

The students in the audience immediately began to whisper.

"It's a bit difficult, isn't this an over-the-top question?"

"Yes, this involves the knowledge points of 'the first n items of the geometric sequence and' in the mathematics compulsory 5 textbook, and those who have not studied it by themselves cannot do it."

"Who told Qin Ke to be so pushy? Teacher Zheng is the most suitable for such super-level questions!"

"Hey, this math problem is not difficult for us, but for Qin Ke, a sleepy god who never listens to lectures or studies... if you want to do it in 3 minutes... hehe."

"Qin Ke will lose face this time, but he doesn't care about his face when he sleeps every day!"

Ning Qingyun listened to the whispers of the students around her, and gave Qin Ke an angry look, look, you are arrogant, you have become the target of public criticism this time, right?

This question is certainly not difficult for her who is the first in grade and has self-study all the subjects of science in high school. It can be easily solved by summing with the subtraction method.However, for students with average or even low-level math scores, it is still a bit tricky to solve such a geometric sequence summation problem, and it is not easy to calculate the answer within 3 minutes.

Ning Qingyun glanced at Qin Ke, do you want to give this guy a little hint?After all, this guy just spoke for himself...

But this is considered to be helping him to cheat, isn't it true for the boys' gossip?

The school committee, which has always been serious and principled, is in trouble.

However, seeing that Qin Ke, who spoke for her, was facing the "cold eyes and ridicule" of countless male classmates, looking so "weak and pitiful", the girl felt soft, sighed secretly, and was about to write down the problem-solving steps in her notebook .

I didn't take the initiative to tell Qin Ke, if Qin Ke sneaks a glance, I can't control it.

但宁青筠刚动笔，就听到秦克平静道：“bn＝15－(4n＋3)×(1/2)^(n－2)。”

Ning Qingyun looked up in astonishment, and the whole class, regardless of gender, was stunned at the same time. Then the male students couldn't help but peek at Lao Zheng's expression, and then began to discuss in a low voice.

"Qin Ke was just talking nonsense. It took less than 20 seconds. How did he come up with the answer? It's impossible to calculate it mentally, right?"

"Is it just trying to save face?"

"I guess so."

"Hush! The teacher will announce the correct answer soon!"

Old Zheng was subconsciously touching the cigarette case in his pocket. Hearing this, he almost crushed the cigarette case. He looked at Qin Ke in shock: "How did you come to this conclusion? Go up to the blackboard and write down the process of solving the problem." .”

Qin Ke curled his lips in disdain: "Such a simple task of giving points, mental calculation is enough, but you still have to write it out? Well, you are the teacher and you are the biggest."

He walked onto the stage, picked up a chalk brush and started writing.

"Solution: a4+2 is the middle term of the arithmetic difference of a3 and a5,
得a3＋a5＝2a4＋4，

所以a3＋a4＋a5＝3a4＋4＝28，

The solution is a4=8.

由a3＋a5＝20，得8（q＋1/q）＝20，

......"

The line-by-line solution process appears smoothly on the blackboard.The students whispered to each other again:
"It's strange. Looking at Teacher Zheng's expression just now, it seems that Qin Ke didn't come up with an answer just randomly..."

"Impossible, how could such a problem be calculated in mind? And it was done in such a short time? I don't believe it! He must have seen this problem not long ago and remembered the answer."

"But he obviously learned the compulsory 5 by himself, and he wrote very fluently."

"Fuck! Qin Ke seems to be doing the right thing, and the steps are all right!"

Ning Qingyun's usually cold eyes also stared at the male tablemate on the stage in surprise.

This guy is 1.8 meters tall, with sharp eyebrows, big eyes, high nose bridge, and good facial features. He looks like a dog, but his natural curly hair looks like he hasn't combed it carefully. His eyes are always half-closed in sleepiness, his school uniform has two buttons unbuttoned, and he looks like a lazy and carefree problem student.

But it's such a lazy guy who actually figured out the correct answer in his head?

Yes, there is no need to read the final steps to solve the problem. Ning Qingyun has already determined that Qin Ke's answer is correct through mental arithmetic.

She couldn't help thinking in shock, this guy... Could it be that he has been hiding his math prowess before?Can such a problem be calculated in ten seconds?If you change yourself, you have to do mental calculations for about 2 minutes!
Under the gaze of countless eyes, Qin Ke on the stage finished the final steps in a hurry:

“所以1/2Tn＝3＋4×1/2＋4×(1/2)^2＋…＋4×(1/2)^(n－2)－(4n－5)×(1/2)^(n－1)，因此Tn＝14－(4n＋3)×(1/2)^(n－2)，n≥2。

又b1＝1，所以bn＝15－(4n＋3)×(1/2)^(n－2)。”

After finishing writing, Qin Ke didn't return to his seat, but turned around provocatively and glanced at the boys in the class, and asked Teacher Zheng: "Mr. Zheng, is my solution correct?"

Zheng Jianzhou was stunned. The answer was correct. It is normal for self-study to choose the mathematics knowledge points in the textbook and solve this problem, but this guy just said the final result when he skipped the steps of solving the problem, right?

How can this be done?Really rely on mental arithmetic?If you really rely on mental arithmetic, what a terrifying mental arithmetic ability!

"Your solution is correct." Old Zheng was overjoyed. This kid usually doesn't look like a mountain, but he didn't expect to be a guy who pretends to be a pig and eats a tiger!It is necessary to seriously test this kid's math ability!He immediately wrote another question: "You do this question again."

"Okay! Let the horse come here, it's better to be difficult, the question just now was too easy!"

Qin Ke didn't bother with Lao Zheng about "just ask a question" before, and the system prompts that kept coming from his ears made him almost unable to help laughing out loud.

The students in the audience are still constantly brushing his hate points, shock points, and even jealousy points and envy points, which makes his experience points of learning gods increase rapidly.

"This kid is a bit arrogant. I hope Mr. Zheng will have a real problem in his debut this time."

"That's right, what's so great about being able to do that question just now, at least half of the students in our class can do it too!"

While the students in the audience were whispering, Zheng Jianzhou's topic had been written.

"The right vertex of the ellipse E: x^2/a^2+y^2/b^2=1 (a is greater than b and greater than 0) is A, the right focus is F, and the upper and lower vertices are B, C, |AB| ＝7^(1/2), straight line CF intersects segment AB at point D, and |BD|＝2|DA|,

(1) Find the standard equation of E;
(2) Is there a straight line l such that l intersects the ellipse at two points M and N, and F is exactly the orthocenter of △BMN?If it exists, find the equation of l; if it does not exist, explain the reason. "

If the question about the sum of geometrical series just now was just a common question with knowledge points beyond the outline, then this question is what Zheng Jianzhou intends to use as the finale of the next monthly exam.

Lao Zheng is very confident about the difficulty of this question. It requires strong spatial thinking and problem-solving skills. It is expected that even Wu Shaocai, the mathematics representative in the class, may not be able to solve it within 5 minutes...

"Qin Ke, come and solve this problem. You will also be given 3 minutes. You can use a pen..." Zheng Jianzhou turned his head, and Qin Ke interrupted, "The first question, ellipse E The standard equation of △BMN is x^2/4+y^2/3=1. In the second question, there is a straight line l, so that F is the orthocenter of △BMN, and the equation of l is y=3^(1/2)x/3－16 *3^(1/2)/21."

Zheng Jianzhou flipped through the answers subconsciously, and they were all right.

He opened his mouth wide and looked at Qin Ke in disbelief. Good guy, did you just calculate the result in your head again?Is this possible?
(End of this chapter)