God-level Xueba system upgrades 999 seconds

After reading the test rules, the test papers were quickly distributed to everyone.

The test paper is divided into 3 questions.

In the first question, let A and B be two points on the hyperbola xy/2=z, point N(1,2) is the midpoint of line segment AB, and the perpendicular bisector of line segment AB intersects the hyperbola at two points CD.

Please determine the value range of z.

"Damn it, should it be so difficult?"

"Teacher, you want to play us to death, don't you?"

"I don't know how to answer the coach question."

"..."

Just seeing the first question, the entire auditorium was filled with wailing.

This question seems to be very short, but the knowledge used is extremely rich.

It covers almost all the knowledge points in the whole high school.

Even though all the people here are at the level of academic masters, they still scratched their heads when they got this question.

Difficult, it is too difficult.

"Hey, who came up with this question? Isn't this just to scold you?"

Qin Luo saw through everything at a glance, without much hesitation, he just picked up his pen and started working!
Let the equation of AB be: y=k(x-1)+2, bring into the hyperbolic equation...

...then the value range of z is (-1,0)U(0,+∞).

Qin Luo frantically wrote down the process of solving the problem. Up to now, he only spent 3 minutes.

"Ten points to get it done." Qin Luo let out a long sigh of relief, burning many brain cells to death.

After checking that it was correct, Qin Luo raised his head and looked around.

A boy on the left was trembling all over, and a girl on the right was biting a pen holder and sweating profusely... Where Qin Luo looked, there was no one writing.

"..." Is it really that difficult?Qin Luo didn't think so.

Suddenly, out of the corner of Qin Luo's eyes, he saw Bai Chong sitting in the corner.

Unlike others who are thinking hard, Bai Chong is writing hard.

A black gel pen drew beautiful arcs in his hand, and the next moment, the answer was already on the paper.

En~, being able to become a top student in Chengyu No. [-] Middle School, you really have two talents.

But Qin Luo didn't care, Bai Chong had two brushes, but he had dozens of them.

What surprised Qin Luo was that Lin Shanshan was also writing quickly.

Well, it seems that I do have the potential to be a teacher. In just a few days, I turned a scumbag into a top student.

Suddenly, Qin Luo felt his eyes dim, and looked up: "Hold the grass, there is someone!"

I saw an invigilator wearing a Chinese tunic suit with a serious expression staring at me intently.

Those scorching eyes seemed to melt him in the next second.

"What are you looking at, do the questions quickly." Feng Huadong said coldly.

Feng Huadong, the invigilator this time, is also the president of the Southwest Provincial Number Federation Association.

"...Teacher, to scare people is to scare people to death."

"Scared you to death? You almost scared us to death." Feng Huadong thought to himself.

Zhou conjectured that a problem that had plagued the mathematics world for more than ten years was actually solved by a high school student. When he heard the news, he was almost frightened to death.

No one would have thought that a student who was still in high school could prove Zhou's conjecture.

I scare you to death?Ha ha... funny.

"Hurry up and do the questions!" Feng Huadong snarled, turned around and left.

"Are all the current invigilators so fierce?" Qin Luo shook his head and devoted himself to solving the problem again.

A few minutes later, Qin Luo started to write again.