Chapter 252: Errors in the paper

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In the afternoon, the grove. ┏Ⅹ④③⑨⑨┛
Cheng Nuo attended the appointment on time after finishing the class.
On a stone table used to rest in the small forest, Wang Genji had already been waiting here.
Seeing Cheng Nuo's arrival, Wang Genji waved at him, "Here, here."
Cheng Nuo came to the stone table and sat opposite Wang Genji.
The grove is an off-travel area on campus. Except for occasional couples who are reluctant to spend money to stay in a hotel, very few people come here.
The wind blew the leaves and made a rattling noise.
In the quiet grove, on a stone table, Cheng Nuo and Wang Genji sat opposite each other.
"Let's start." Wang Genji glanced at Cheng Nuo, took off his jacket, and spoke slowly.
Cheng Nuo nodded slightly and exhaled deeply, "Well, senior, come on!"
Wang Genji took out a stack of a4 paper from the bag beside him.
That is his paper printed in advance. There are seven pages in total.
He handed the printed paper to Cheng Nuo and looked at Cheng Nuo eagerly, "Can you tell me now, which step is wrong in my paper?"
All night yesterday, because he kept thinking about it, he didn't sleep well all night.
No, this afternoon, he came to this small forest just after lunch, and waited for Cheng Nuo early.
Even if you die, you must die to understand.
Wang Genji didn't know if he could rescue this paper. But at least, he needs to know where he went wrong.
Cheng Nuo smiled and accepted the paper, shrugged, "Of course."
Cheng Nuo took a pen out of his pocket, turned to the second page of the paper, and drew a line under a formula. "Hey, it's this step. Senior, how did you get this formula from the previous formulas?"
The formula Cheng Nuo drew was one of the first derivation formulas of the new type of solution proposed by Wang Genji.
In the paper, Wang Genji wrote that a bck-scholes stochastic differential equation, for example: d=1
Write the pseudo-homogeneous differential equation of this stochastic differential equation, d=σdb, so
Set another equation f=ce^σbt, and substitute the maximum and minimum values ​​obtained from the first-order derivation into the pseudo-homogeneous differential equation of the original equation, and then use Riemann integral to solve, and finally use the ito formula Differentiate.
The key is the process of substituting the maximum value of the first-order derivative of f written by Wang Genji.
"What's wrong, is there any problem with this step?" Wang Genji looked confused.
He thought Cheng Nuo would say that his mistake was in the middle and later part of this paper.
After all, the formula calculation steps in the latter part of the paper are too many and too complicated.
Wang Genji couldn't be 100% sure whether he would make a mistake somewhere.
But Cheng Nuo pointed out what he showed himself, but there are several formulas at the top of the paper.
Seeing that Wang Genji's mind hadn't turned around yet, Cheng Nuo frowned slightly, and patiently explained, "Senior, you set a f=ce^σbt here, and then set the maximum and minimum of its first derivative. Substitute the value."
"But how can you be sure that the first-order reciprocal of the f you set must have a maximum or minimum value?"
"+ and-are both possible!"
"When the maximum value of the first derivative is positive infinity, or the minimum value is negative infinity, the following formula is simply impossible."
Cheng Nuo finished his judgment word by word.
Opposite Cheng Nuo, after hearing Cheng Nuo's words, Wang Genji's complexion had turned pale.
wrong! It is really wrong!
This place, he was really wrong!
When he was writing this section, he just touched it in one stroke. In other words, some take it for granted.
It has not considered that there will be no maximum and minimum values.
As a result, a small mistake caused the entire paper to collapse.
Now, after more than four months of hard work, all have come to nothing.
Unwilling! Really unwilling! !
But what is the alternative.
There is such a big mistake in the paper, even if it is overhauled, I am afraid it can't be rescued.
It's out of play!
Wang Genji smiled bitterly, picked up the paper on the stone table, shredded it suddenly, and threw it into the air.
The shattered pieces of paper were sprinkled down one after another.
Wang Genji looked like he was unlovable.
Cheng Nuo looked at Wang Genji with a dazed expression, "Senior, why did you tear up the paper?"
Wang Genji was taken aback for a moment, and said in an extremely painful tone, "Cheng Nuo, you don't need to comfort me, I have already looked away."
"Isn't it just a sci paper, trivial, really, trivial."
"This paper is considered useless anyway, and it's boring no matter how sad. I will have the opportunity in the future that I will try my best to write a satisfactory sci paper."
After that, Wang Genji got up, put his schoolbag on his back, and left.
That back figure is bleak and desolate.
Cheng Nuo stopped Wang Genji, "Senior, I didn't seem to say that this paper cannot be revised!"
"What?!" Wang Genji suddenly turned around and looked at Cheng Nuo with a deep shocked look, "Cheng Nuo, what did you just say?"
Cheng Nuo repeated the words with a smile, "Senior, your paper is actually not as bad as you think. If you change it, it should still work."
"Are you telling the truth?"
"Senior, I don’t have to lie to you. The simple solution of the linear stochastic differential equation you proposed in your paper, I also calculated it. In theory, this kind of pseudo-homogeneous equation is first sought, and then the variable constant is used to verify the solution. The method is indeed feasible. However, in the specific calculation process, it needs to be carefully considered."
After listening to Cheng Nuo's words, the expression on Wang Genji's face quickly changed from overcast to clear.
Just save! Just save it!
He continued to sit opposite Cheng Nuo, looking at Cheng Nuo with a cordial gaze, and opening his face full of light, "Cheng Nuo, come, let's discuss it in depth."
Subconsciously, Wang Genji wanted to take out the printed paper from his schoolbag. Then I realized tragically that the paper had been torn to pieces by myself. UU Reading www.uukanshu.com
No way, Wang Genji could only climb under the stone table, trying to put the torn paper back together.
It just so happened that at this moment, a cleaning lady passed by here. Glancing in the direction of Shizhuo, his eyes widened.
From her perspective, at the stone table, there are two boys, one is lying under the stone table, kneeling on both knees, supporting the ground with both hands, and the head is blocked by the legs of the other boy. More importantly, the body of the boy lying under the stone table kept moving back and forth. The other boy leaned back slightly, with a very comfortable expression.
That picture, tut tut
"Are young people now so open?"
The cleaning aunt felt that she was really old. Is the current social atmosphere so open?
The auntie cleaning reminded them kindly and shouted loudly. "Hey, two boys, don't do any foreplay, hurry up and do it. I saw someone coming towards this place."
Cheng Nuo + Wang Genji: "???"