Super Xueba: Start With A Low Control Score!

Chapter 52 The horror is like this, this son is not human!

The invigilator was speechless.

I was shocked.

What is Xiu’er?

This is Xiu’er.

He has been teaching for nearly two decades.

He has never seen what kind of mathematical genius.

But those so-called geniuses compared with Jiang Nan, they are all scum, and they are not on the same level at all.

this point……

It can be seen from the fact that Jiang Nan has directly completed the last question of the test paper in less than ten minutes.

and……

According to Cao Tianyuan.

Jiang Nan is still 100% correct in solving problems.

even……

The draft papers specially issued for the math test are all clean, with no words written on them.

You should know that some students next to you have not finished the multiple-choice questions, but have used up a piece of draft paper.

hiss……

What kind of Luo Ji thinking and spatial thinking does a person have to achieve Jiang Nan’s step?

At the same time.

Jiang Nan as a party.

I didn’t care about the shock of the two invigilators behind me, just a quick “swish”.

to him.

These questions are too challenging.

Just want to finish it quickly, sleep is king.

but……

When doing the last question of the paper.

His eyes narrowed slightly.

“Ah!”

“Finally, I came across an interesting question. It seems that this paper is not useless.”

Prior to this, Jiang Nan reviewed the questions in one second, and then he could get the answer in an instant.

However……

This last finale.

He watched it for a few seconds.

visible……

The difficulty of this question.

I don’t know how much it exceeds the previous ones.

The original title is as follows…

“The known function f(x)=1/√(1+x)+1/√(1+a)+√(ax/(ax+8)), x belongs to (0, +∞).

(1) When a=8, find the monotonic interval of f(x).

(2) For any positive number a, prove: f(x) is greater than 1, but less than 2. ”

Similar to the first question of the solution question.

This last question is also a function problem.

but……

the difference is.

This involves monotonicity, inequality.

It feels a bit more difficult than the previous question.

but……

For Jiang Nan.

It’s only a little bit interesting.

The word “difficult”.

This could not have appeared in his mind.

untie……

When a=8.

f(x)=(1+√x)/√(1+x)+1/3.

Find the derivative to get f`(x)=(1-√x)/2√(x(1+x)^3.

So when x belongs to (0, 1).

f`(x) is greater than or equal to 0.

When x belongs to [1, +∞).

f`(x) is less than or equal to 0.

So f(x) increases monotonically on (0, 1], and decreases monotonously on [1, +∞).

…

What is Penzou Dragon Snake?

This is the pen to go to the dragon and snake.

After Jiang Nan wrote the word “solution”, he didn’t pause anymore, and directly made the first question.

Gee!

One word, absolutely.

A certain invigilator behind him can no longer come over, just because he is not teaching mathematics, and Jiang Nan’s problem-solving speed is so fast that he can’t understand it at all.

but……

It’s also because I can’t understand it.

Instead, I have to calm down a lot.

on the contrary.

When Cao Tianyuan saw Jiang Nan, he immediately completed the first question of the last question, his pupils shrank again, his expression moved, and his heart was overwhelmed.

f*ck!

Great, strong!

Jiang Nan is really going against the sky.

The invigilator next to him knew that the final math question was difficult, but he didn’t know how difficult it was.

However……

Cao Tianyuan knew it.

after all……

He is a senior math teacher.

Although this question is not complicated at first glance, it is only at first glance.

Actually…

It’s really very difficult.

Even if he came to do this problem, it didn’t cost 80 to 90% of the work, and he really couldn’t solve it.

It is not an exaggeration to say that this is the most difficult monthly test finale he has ever encountered. It can surpass the final test of the college entrance examination several times, and can even compete with the finale of the Olympiad.

but……

Did Jiang Nan get it done with no effort?

It’s incredible.

Not a person!

It’s really not a human being.

He has not dared to take Jiang Nan as a student.

Where is this still a student?

Obviously he is a senior professor of mathematics, okay!

He himself is far less than the kind.

Can……

The matter has not ended there.

Just when Cao Tianyuan sighed, Jiang Nan had already started to do the second question, and the speed was still very fast.

(1) The proband f(x) is greater than 1.

Because 1/√(1+x)>1/(1+x).

…

so……

f(x)=(1+(a+b+x)+(ab+ax+bx)+abx)/(1+x)(1+a)(1+b).

(2) Re-prove that f(x) is less than 2…

…

That is, ab+8 is greater than (1+a) (1+b).

That is, a+b is less than 7.

…

In summary, for any positive number a, x, f(x) is greater than 1, but less than 2.

Jiang Nan answered.

It was done in one go, and the second question was done lightly.

In other words…

Jiang Nan has finished the exam?

See here.

Behind a certain invigilator subconsciously glanced at the clock on the blackboard, and found that it was only…nine minutes before the test began?

Damn it!

It took only nine minutes to take the test?

It didn’t arrive for ten minutes.

Did Jiang Nan finish the whole paper?

Horrible!

This son is not human!

If he hadn’t seen it with his own eyes, or beat him to death and burned to ashes, he couldn’t believe it.