The love of functions and derivatives

"Papapapa——" the delivery guy clapped his hands, "As expected of a derivative, smart man. He Jun is indeed a lunatic, and we have the same position on this issue."

The takeaway boy's eyes suddenly showed hatred: "Crazy He has brought out students from Tsinghua University, but so what? He can't even teach his own son's math well! A man who puts all his energy on teaching himself, Stupid and overconfident high school math teacher who doesn't care about relatives and family!"

"He's just a mediocre but proud teacher." Derivative doesn't care about the delivery boy's attitude towards He Jun, he just wants to know the purpose of the delivery boy's trip, "What do you want to talk to me about? Or, What do you want to know?"

"Then I'll be honest, what did He Jun do to you when you traveled to the world of high school mathematics textbooks for the last time?" In order to let the derivative tell the truth, the takeaway boy specially emphasized, "As long as you answer my question honestly, I will It will return to the human world immediately, and will never come again."

The derivative took a deep look at the delivery boy.

never again?He doesn't believe it.

"The last time, He Jun wanted to kill me." Derivative said succinctly, "He pierced my heart with a steel bar, but he failed to kill me, that's all."

The takeaway boy's expression changed slightly, and he questioned: "He Jun has been to this high school mathematics textbook world three times in total, and he failed to kill him twice before. Why would he try to assassinate the third time? Don't you think this is illogical? ?”

Seeing the change in the delivery boy's expression, the derivative suddenly had a guess—the delivery boy might want to know from himself how to really kill the function.If this is really the purpose of the delivery guy, then he knows what he should say, and the derivative begins to take the initiative of the conversation into his own hands.

"Because he forgot." Derivative sneered disdainfully, "Actually, I can guess what happened when you returned to the human world after you did it."

"For a while after the function is injured, all the math textbooks in a high school have chapters on functions that disappear, and you are happy because your goal of eliminating functions has been achieved, but after a month, those missing chapters are restored, because The injury of the function is healed. All the students will forget that the textbook was missing, this is the repair mechanism of the textbook world, and you, because you have been to the textbook world, your memory will be kept longer, but you will still forget it .”

The takeaway guy is still a 19-year-old boy after all, he was a little shocked, which was within the expectation of the derivative: "Then what you mean is that He Jun forgot the fact that you can't be killed, so he treated you again for the third time." Do it?!"

Derivative nodded: "So, you should give up. Functions cannot be eliminated. Although some chicken soup is old-fashioned, it also makes sense. You should go back to the classroom to defeat functions instead of destroying functions."

"But the function should be damned!" The takeaway boy's eyes were stern, and because of his excitement, the takeaway boy's voice was raised by an octave, "How many students have cold scalps because of him staying up all night? How many students have lost their ideals because of mathematics Missed?"

"But it's not the function's fault." Derivative didn't receive any temptation from the delivery boy, and said calmly, "You will encounter more difficulties in the future, which are far more difficult than the function. At that time, these difficulties will not be eliminated. You can only bite the bullet."

"Furthermore, if you don't choose a major in college, you will have to learn advanced mathematics in the future. Advanced mathematics requires a lot of basic mathematics. All your laziness now will be paid back with your hair in the future."

The takeaway boy didn't speak.

Derivative didn't know if he listened or not. After a while, the delivery boy said, "Since you are honest with each other, I will keep my promise."

The takeaway boy stabbed himself in the chest with a knife, and the bright red blood stained the tip of the knife. The next second, the delivery boy's body became transparent, and the knife hit the ground, shaking even the floor of the derivative station. In an instant, the blood on the knife also disappeared.

Derivative looked down at the dagger on the ground, wondering what he was thinking.

Derivative had a nightmare that night. The nightmare was not continuous, but some fragmented fragments.

The man in the dream said to himself with a horrifying smile: "The derivation formulas in high school mathematics textbooks are given directly to students without proof. This is not in line with the logic of mathematics learning, so why should students believe in derivatives?" correct?!"

"Why? Why can't I rewrite the chapter on derivatives!"

"There are usually only two endings for imperfect things, one is to remodel, and the other is to destroy it directly. Obviously, I tried the first method, but it didn't work, so I can only—" The man's voice stopped abruptly , the right hand holding the knife pierced the thin air, brought out a gust of wind, and slashed fiercely towards his neck——

Derivative woke up from the nightmare, breathing heavily.

False, it's all over.

In the middle of the night, the derivative who was awakened by the nightmare closed his eyes again. Even though there was no sound outside the window, and there were no annoying cicadas, the derivative never fell asleep again until dawn in the east.