Chapter VI

Wednesday.

Early in the morning, Gu Lu just pushed open the door of the office of the mathematics group, and before he entered, he saw Teacher Sun Ya coming over with a smile from the office of the English group next door with a gust of incense.

"Teacher Gu, I brought glutinous rice balls, let's try them. ”

It can be seen that Sun Ya is carefully dressed up today.

The long silky hair was draped vertically over the shoulders, the snow-white long sleeves were close to the body, outlining the delicate curves, coupled with eye shadow and a touch of blush, which instantly amazed several young male teachers in the math group.

But at this time, Sun Ya's attention had already been focused on Gu Lu.

As a result, several young male teachers in the mathematics group could only watch Sun Ya follow Gu Lu all the way to the desk with a sad and angry face.

Then, Sun Ya pulled a chair and sat beside Gu Lu, holding her cheeks, and watched Gu Lu eat glutinous rice balls one bite at a time, her heart full of satisfaction.

Zhou Haihong came later this time, and when he saw Gu Lu and Sun Ya sitting together, he walked over with some doubts.

"Teacher Sun, I'm here to send glutinous rice cakes again, let me taste it, has there been any progress in my craftsmanship this time. Zhou Haihong stretched out his hand to get it.

But Sun Ya was even quicker, and quickly dragged the plastic box containing glutinous rice cakes to the side and protected it in her hand.

"Teacher Zhou, these are specially brought by me for Teacher Gu today, if you want to eat, I will bring them to you tomorrow!" Sun Ya opened her mouth apologetically, and tightly protected the box of glutinous rice cakes in her hand, looking like she was not being touched by Zhou Haihong.

Zhou Haihong looked at Sun Ya, and then at Gu Lu who showed an innocent expression, and his heart ached instantly.

What a good little girl Teacher Sun was before!

Not to mention the beauty and kindness, she will also bring some small desserts made at home from time to time to share with the teachers.

But now, they have left behind their group of teachers who have worked together for more than a year, and they are completely confused by Gu Lu, and even the desserts they brought are exclusive to Gu Lu.

Alas!

Zhou Haihong let out a long sigh, shook his head, stepped aside, and began to play Baduanjin.

"The first section of Baduanjin, holding Tianli Sanjiao with both hands, hey!"

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"Students, in class, in today's class, you have only one task, and that is to solve the problem I wrote. ”

It's time for Teacher Gu's class again.

After saying this, Gu Lu picked up the chalk and wrote a question on the blackboard.

[The tangent equation of the function f(x)=alnx/x+1+b/x, the curve y=f(x) at the point (1, f(1)) is x+2y-3=0.

(1). Find the values of a and b.

(2). If x>0 and x≠1, f(x)>alnx/x-1+k/x, find the value range of k. 】

"The first question is too simple, so in order to avoid wasting time, I will give you the answer directly. A is 1 and B is also 1. Gu Lu directly wrote the answer to the first question on the blackboard, "What you need to do now is to solve the second question of this question." ”

"I need to tell you that there is more than just one solution to this problem, and what I need you to do is to diverge your thinking and come up with as many solutions as possible. ”

This question was accidentally swiped by Gu Lu on the Internet, and he found it interesting, so he brought it to the students to try it.

The reason why Gu Lu finds it interesting is not how difficult this question is, in terms of difficulty, this question is not even as good as the finale of the college entrance examination.

Instead, Gu Lu found that the second question of the question had a variety of different solutions, and there were more than a dozen of them.

That's a lot of fun!

"If someone has an idea, they can just come up and write it down on the board. Okay, I'll leave the time to you. After Gu Lu finished speaking, he retreated to the side of the podium and moved a chair to sit down.

Almost the moment Gu Lu sat down, a figure below stood up and walked directly onto the podium with extremely confident steps.

Gu Lu glanced sideways slightly, and found that the first person to be in the limelight was indeed Bi Qi, a kid.

The students let out an exclamation as expected.

Bizzie's speed was just too fast.

Some of them hadn't finished reading the question yet, so Bizzie was ...... Figured out how to solve the problem?

Sure enough, Bi Qi deserves to be a big guy with a perfect score in mathematics!

On the podium, Bi Qi smiled at Gu Lu with a satisfied face, picked up the chalk, and wrote on the blackboard with great momentum.

[From a=1,b=1, we know that f(x)=lnx/x+1+1/x.so,f(x)-(lnx/x-1+k/x+k/x)=1/1-x^2(2lnx+(k-1)(x^2-1)/x).

The function h(x)=2lnx+(k-1)(x^2-1)/x,x>0, then h'(x)=(k-1)(x^2+1)+2x/x^2.

(i) When k≤0, it is known from h'(x)=(k-1)(x^2+1)+2x/x^2, and when x≠1......]

Biqi's problem-solving steps are decent. First, the function h(x) is constructed and derived, and then the value range of k is solved by discussing the magnitude of h(x) in the three cases of k≤0<0k<1, k≥1, and k1.

"So, at the end of this question, the value range of k should be (-∞,0]!"

Biqi confidently wrote down the results.

Gu Lu nodded, indicating that the answer was correct.

Below, the students were amazed.

"Wow, Bi Qi is so amazing!"

"Worship the math gurus!"

"666, kneel for the big guy!"

In the face of admiration, Bi Qi waved his hand indifferently, "Ji Cao, don't 6!"

"That's right, teacher. Bi Qi turned to look at Gu Lu, "Is it possible that each person can only write one solution?" ”

The corners of Gu Lu's mouth curled, "If you can, there is no problem in writing as many solutions as you want." ”

Bi Qi picked up the chalk, thought in silence, and then put the chalk down.

"Well, forget it, leave some opportunities for the other students, otherwise it will be a bit too much. Bi Qi shook his head, sighed, and sat back in his seat.

Gu Lu was speechless, and finished watching Qi's pretending performance.

This guy ......

Gu Lu had a feeling that he didn't know what to evaluate.

He rubbed his eyebrows and said helplessly, "The next classmate who has an idea will come up directly." ”

Half a minute later, Ma Zhengxuan came up with a sketchbook and wrote down his own solution ideas.

Ma Zhengxuan's solution idea is also a conventional solution, which is to analyze the situation discussion by finding the quadratic derivative of the function. In terms of specific steps, it is more complicated than Bizzie's solution.

For high school students who are not deeply poisoned by exam-oriented education, it is indeed difficult to let them have some thinking that breaks through common sense.

In addition to Bi Qi and Ma Zhengxuan, another student in the class who scored well in mathematics wrote down his own solution.

Since then, no classmates have come up to try.

Seeing that there were still ten minutes before the end of class, Gu Lu stood up helplessly.

I can't help it, I still have to play!

"I don't think time is running out, and since the students don't have any new ideas, I'll talk about a few solutions that I have come up with. Gu Lu said loudly, "You guys, watch it well, listen to it well!"

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