"Liu Yichen, I like the birthday gift you gave me very much~~" Feng Lin suddenly said as she walked into the dormitory building, then her face turned slightly red, and she walked up the stairs quickly, leaving only Liu Yichen's back.

Liu Yichen did it inexplicably.

If you like it, you like it, why are you blushing?

But Liu Yichen also breathed a sigh of relief. Fortunately, Feng Lin didn't see the postcard he wrote, otherwise she wouldn't be able to clean herself up even if she jumped into the Yellow River.

After returning to the dormitory, Liu Yichen took a shower, washed his clothes and hung them to dry on the balcony. Then Liu Yichen went to the classroom for evening self-study.

During self-study in the evening, all the classmates couldn't help but look at him, muttering secretly, it's just that he is handsome, and his academic performance is so good. If it was just like this, everyone could barely accept it, but Liu Yichen

He was so good at basketball that he joined the school team and played in an internal game of the school team. With his beautiful posture, he attracted countless fans.

Although Liu Yichen was very unhappy to be watched, as if he felt like an animal in the zoo being watched, he adjusted his attitude and entered the question-answering state. He began to do the Huanggang Secret Paper. Huanggang didn't know what was going on. Education was terrible.

As a result, various Huanggang Secret Scrolls became popular all over the country. Almost every student who wanted to learn would have a set of Huanggang Secret Scrolls. Liu Yichen did not buy this set of Huanggang Secret Scrolls, but borrowed them from the library. It did not cost money, but it could not

Any drawings on it.

Speaking of which, there are several legends in Huaxia High School, and Hengshui Middle School and Huanggang are two of them.

Hengshui Middle School is definitely a legend. It measures vacation time in "hours". It has a vacation once every two weeks or three weeks, and a vacation lasts 24 hours. This makes hotels within a 5-kilometer radius of Hengshui Middle School,

It is always full on a specific day or two every month, and the price is more expensive than a hotel of the same level in the city center of HS. There are some properties for rent or newly opened for sale next to the flat wheat fields and low newly planted sycamore trees.

, named "xx School", the price is almost the same as the urban housing prices, or even higher. Many people choose to rent or buy here just to facilitate a few hours of meeting with their children every month during their holidays. Other high schools have

There are still "xx days" before the college entrance examination. Hengshui Middle School directly came to "sprint for 7 days and race against time to seize the opportunity for the second year of high school."

There are still 12 days, 5 hours, 51 minutes and 27 seconds left." The countdown to the college entrance examination is calculated directly in seconds.

The "College Entrance Examination Factory" has become famous all over the country since then, and people can't help but marvel. Of course, what is even more amazing is that Hengshui Middle School was successfully listed in the United States!

The Huanggang Secret Scroll is also resounding in high school circles across the country. When people mention Huanggang, the first thing that comes to their mind is not the city of Hg, but Huanggang Middle School and the Huanggang Secret Scroll.

There is a saying in high school circles, if you are confident in your mathematics, please do the Huanggang Secret Paper; if you don’t want to fall into complacency, please do the Huanggang Secret Paper; if you want to improve your math skills in the eyes of the whole class with envy

Ge, please swallow your tears and make Huanggang secret scroll...

What Liu Yichen is working on now is the Huanggang Secret Volume of Mathematics.

A true warrior always dares to challenge the bleak life!

And Liu Yichen is undoubtedly the real warrior.

I have to say that this Huanggang Secret Paper is much more difficult than the after-school exercises and exercises in the exercise book. Many of the questions test comprehensive knowledge quite well, and even the real college entrance examination questions are not necessarily that difficult.

"Interesting, this question is very interesting!" Liu Yichen looked at a question. This question not only tested set knowledge, but also tested function knowledge.

This question is like this. It is known that the complete set s={1,3,x^33x^22x}, a={3,|2x-11|}, if csa={0}, does such a real number x exist?

?If it exists, find x; if it does not exist, please explain the reason.

Liu Yichen drew a square shape for the set s and a circle for the set a. The sum of the set s minus the set a belongs to csa, which is the complement of the set a relative to the set u.

That is to say, if it exists, then x^33x^22x=0. Liu Yichen adjusts this equation to x(x1)(x2)=0, thus finding x=0 or x=-1 or x=-2, so

There are three situations to find a, namely a={3,11}, a=(3,13), a=(3,15). And when a={3,1}, it means |2x

-11|=1, that is to say, x=6 or x=5, the two cannot be unified, so there is no real number x, making csa={0}.

Later, when doing a function question, Liu Yichen frowned slightly. The question was very simple: given function f(x)=x^2x,x≥0;-(1-2x)^-0.5,x<0, find

The inverse function of f(x).

Such a question has already tested power functions and inverse functions.

Function has always been a very important field in high school mathematics. It runs through the entire high school mathematics and is also a required content for the college entrance examination. The score ratio is quite large. Functions often involve power functions, exponential functions, logarithms, and inverses.

Common forms such as functions and their properties.

Liu Yichen drew the graph of f(x) on the scratch paper. According to the characteristics of the inverse function, that is, the inverse function of y=f(x) is y=f-1(x), and then compared the domain of the function with

One-to-one mapping of value ranges.

"Nima, the Huanggang secret paper is really perverted. The mathematics secret paper for the first year of high school dares to be so difficult. Are you trying to torture people?" Liu Yichen complained secretly. This is simply too much. If you get such a result in the mid-term or final exam,

As for the question, it is estimated that among the first-year students in high school, there will definitely be many students who become confused while doing it, and then cry secretly, and can only silently write the word "solution".

Unconsciously, Liu Yichen made two volumes of Huanggang secret papers. The evening self-study was over. Liu Yichen checked the reference answers one by one. When the checking was completed, he was the only one left in the whole classroom.

"It seems that I have not fully mastered Mathematics Compulsory Course 1. I failed to solve one question and failed to answer three questions correctly." Liu Yichen muttered secretly: "Sure enough, I am not yet a top student, and there is still a long way to go before I can become a top student.

distance!"

Maybe if you are really a top student, you can easily kill monsters by doing this Huanggang Secret Paper. Doing this kind of questions is no different from drinking water.

Liu Yichen felt a little dizzy, so he immediately packed his things into his backpack, then picked up his backpack and turned off the lights in the classroom, and took a walk on the playground to relax his brain.

Making this Huanggang Secret Roll is really nerve-wracking. If you don't pay attention, you will make mistakes.

Suddenly, Liu Yichen stopped and saw Feng Lin studying at the flag-raising platform. Under the dim light, Feng Lin with short hair appeared to have a unique beauty, which was both pure and serious.

Sure enough, not only serious boys are handsome, serious women are also very beautiful.
Chapter completed!